-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/array.sgml,v 1.21 2002/08/05 19:43:30 petere Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/array.sgml,v 1.22 2002/09/21 18:32:52 petere Exp $ -->
<sect1 id="arrays">
<title>Arrays</title>
<note>
<para>
A limitation of the present array implementation is that individual
- elements of an array cannot be SQL NULLs. The entire array can be set
- to NULL, but you can't have an array with some elements NULL and some
+ elements of an array cannot be SQL null values. The entire array can be set
+ to null, but you can't have an array with some elements null and some
not. Fixing this is on the to-do list.
</para>
</note>
around the array value plus delimiter characters between adjacent items.
The delimiter character is usually a comma (<literal>,</>) but can be
something else: it is determined by the <literal>typdelim</> setting
- for the array's element type. (Among the standard datatypes provided
+ for the array's element type. (Among the standard data types provided
in the <productname>PostgreSQL</productname> distribution, type
<literal>box</> uses a semicolon (<literal>;</>) but all the others
use comma.) In a multidimensional array, each dimension (row, plane,
if they are empty strings or contain curly braces, delimiter characters,
double quotes, backslashes, or white space. Double quotes and backslashes
embedded in element values will be backslash-escaped. For numeric
- datatypes it is safe to assume that double quotes will never appear, but
- for textual datatypes one should be prepared to cope with either presence
+ data types it is safe to assume that double quotes will never appear, but
+ for textual data types one should be prepared to cope with either presence
or absence of quotes. (This is a change in behavior from pre-7.2
<productname>PostgreSQL</productname> releases.)
</para>
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/charset.sgml,v 2.28 2002/09/18 20:09:31 petere Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/charset.sgml,v 2.29 2002/09/21 18:32:52 petere Exp $ -->
<chapter id="charset">
<title>Localization</>
</row>
<row>
<entry><literal>LATIN1</literal></entry>
- <entry>ISO 8859-1 ECMA-94 Latin Alphabet No.1</entry>
+ <entry>ISO 8859-1 <acronym>ECMA</>-94 Latin Alphabet No.1</entry>
</row>
<row>
<entry><literal>LATIN2</literal></entry>
- <entry>ISO 8859-2 ECMA-94 Latin Alphabet No.2</entry>
+ <entry>ISO 8859-2 <acronym>ECMA</>-94 Latin Alphabet No.2</entry>
</row>
<row>
<entry><literal>LATIN3</literal></entry>
- <entry>ISO 8859-3 ECMA-94 Latin Alphabet No.3</entry>
+ <entry>ISO 8859-3 <acronym>ECMA</>-94 Latin Alphabet No.3</entry>
</row>
<row>
<entry><literal>LATIN4</literal></entry>
- <entry>ISO 8859-4 ECMA-94 Latin Alphabet No.4</entry>
+ <entry>ISO 8859-4 <acronym>ECMA</>-94 Latin Alphabet No.4</entry>
</row>
<row>
<entry><literal>LATIN5</literal></entry>
- <entry>ISO 8859-9 ECMA-128 Latin Alphabet No.5</entry>
+ <entry>ISO 8859-9 <acronym>ECMA</>-128 Latin Alphabet No.5</entry>
</row>
<row>
<entry><literal>LATIN6</literal></entry>
- <entry>ISO 8859-10 ECMA-144 Latin Alphabet No.6</entry>
+ <entry>ISO 8859-10 <acronym>ECMA</>-144 Latin Alphabet No.6</entry>
</row>
<row>
<entry><literal>LATIN7</literal></entry>
</row>
<row>
<entry><literal>LATIN10</literal></entry>
- <entry>ISO 8859-16 ASRO SR 14111 Latin Alphabet No.10</entry>
+ <entry>ISO 8859-16 <acronym>ASRO</> SR 14111 Latin Alphabet No.10</entry>
</row>
<row>
<entry><literal>ISO-8859-5</literal></entry>
- <entry>ECMA-113 Latin/Cyrillic</entry>
+ <entry><acronym>ECMA</>-113 Latin/Cyrillic</entry>
</row>
<row>
<entry><literal>ISO-8859-6</literal></entry>
- <entry>ECMA-114 Latin/Arabic</entry>
+ <entry><acronym>ECMA</>-114 Latin/Arabic</entry>
</row>
<row>
<entry><literal>ISO-8859-7</literal></entry>
- <entry>ECMA-118 Latin/Greek</entry>
+ <entry><acronym>ECMA</>-118 Latin/Greek</entry>
</row>
<row>
<entry><literal>ISO-8859-8</literal></entry>
- <entry>ECMA-121 Latin/Hebrew</entry>
+ <entry><acronym>ECMA</>-121 Latin/Hebrew</entry>
</row>
<row>
<entry><literal>KOI8</literal></entry>
</row>
<row>
<entry><literal>TCVN</literal></entry>
- <entry>Vietnamese TCVN-5712(Windows CP1258)</entry>
+ <entry>Vietnamese <acronym>TCVN</>-5712 (Windows CP1258)</entry>
</row>
<row>
<entry><literal>WIN874</literal></entry>
<important>
<para>
- Not all APIs supports all the encodings listed above. For example, the
+ Not all <acronym>API</>s supports all the encodings listed above. For example, the
<productname>PostgreSQL</>
JDBC driver does not support <literal>MULE_INTERNAL</>, <literal>LATIN6</>,
<literal>LATIN8</>, and <literal>LATIN10</>.
<para>
<productname>PostgreSQL</productname> supports an automatic
encoding conversion between server and client for some
- encodings. The conversion info is stored in pg_converson system
+ encodings. The conversion info is stored in <literal>pg_conversion</> system
catalog. You can create a new conversion by using <command>CREATE
CONVERSION</command>. PostgreSQL comes with some predefined
conversions. They are listed in <xref
<para>
Using client_encoding variable.
- If client_encoding variable in postgresql.conf is set, that
+ If the <varname>client_encoding</> variable in <filename>postgresql.conf</> is set, that
client encoding is automatically selected when a connection to the
server is made. (This can subsequently be overridden using any of the
other methods mentioned above.)
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/client-auth.sgml,v 1.38 2002/09/18 20:09:31 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/client-auth.sgml,v 1.39 2002/09/21 18:32:52 petere Exp $
-->
<chapter id="client-authentication">
<term><literal>password</></term>
<listitem>
<para>
- Same as "md5", but the password is sent in cleartext over the
+ Same as "md5", but the password is sent in clear text over the
network. This should not be used on untrusted networks.
See <xref linkend="auth-password"> for details.
</para>
<para>
For local connections, this only works on machines that
- support Unix-domain socket credentials (currently Linux,
- FreeBSD, NetBSD, and BSD/OS).
+ support Unix-domain socket credentials (currently
+ <systemitem class=osname>Linux</>, <systemitem
+ class=osname>FreeBSD</>, <systemitem class=osname>NetBSD</>,
+ and <systemitem class=osname>BSD/OS</>).
</para>
<para>
if you trust every user on every machine that is allowed to connect
to the postmaster by the <filename>pg_hba.conf</> lines that specify
<literal>trust</>. It is seldom reasonable to use <literal>trust</>
- for any TCP connections other than those from localhost (127.0.0.1).
+ for any TCP connections other than those from <systemitem>localhost</> (127.0.0.1).
</para>
</sect2>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/datatype.sgml,v 1.103 2002/09/18 21:35:20 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/datatype.sgml,v 1.104 2002/09/21 18:32:52 petere Exp $
-->
<chapter id="datatype">
implied <literal>UNIQUE</literal>. This is no longer automatic. If
you wish a serial column to be <literal>UNIQUE</literal> or a
<literal>PRIMARY KEY</literal> it must now be specified, same as with
- any other datatype.
+ any other data type.
</para></note>
</sect2>
</sect1>
<listitem>
<para>
The default time zone is specified as a constant integer offset
- from GMT/UTC. It is not possible to adapt to daylight-saving
+ from <acronym>GMT</>/<acronym>UTC</>. It is not possible to adapt to daylight-saving
time when doing date/time arithmetic across
<acronym>DST</acronym> boundaries.
</para>
<row>
<entry><type>regproc</></entry>
- <entry>pg_proc</entry>
+ <entry><structname>pg_proc</></entry>
<entry>Function name</entry>
<entry>sum</entry>
</row>
<row>
<entry><type>regprocedure</></entry>
- <entry>pg_proc</entry>
+ <entry><structname>pg_proc</></entry>
<entry>Function with argument types</entry>
<entry>sum(int4)</entry>
</row>
<para>
Another identifier type used by the system is <type>xid</>, or transaction
- (abbreviated xact) identifier. This is the datatype of the system columns
+ (abbreviated <abbrev>xact</>) identifier. This is the data type of the system columns
<structfield>xmin</> and <structfield>xmax</>.
Transaction identifiers are 32-bit quantities. In a long-lived
database it is possible for transaction IDs to wrap around. This
<para>
A third identifier type used by the system is <type>cid</>, or command
- identifier. This is the datatype of the system columns
+ identifier. This is the data type of the system columns
<structfield>cmin</> and <structfield>cmax</>.
Command identifiers are also 32-bit quantities. This creates a hard
limit of 2<superscript>32</> (4 billion) SQL commands within a single
<para>
A final identifier type used by the system is <type>tid</>, or tuple
- identifier. This is the datatype of the system column
+ identifier. This is the data type of the system column
<structfield>ctid</>. A tuple ID is a pair
(block number, tuple index within block) that identifies the
physical location of the tuple within its table.
The <productname>PostgreSQL</productname> type system contains a number
of special-purpose entries that are collectively called
<firstterm>pseudo-types</>. A pseudo-type cannot be used as a column
- datatype, but it can be used to declare a function's argument or result
+ data type, but it can be used to declare a function's argument or result
type. Each of the available pseudo-types is useful in situations where
a function's behavior does not correspond to simply taking or returning
- a value of a specific SQL datatype.
+ a value of a specific SQL data type.
</para>
<para>
<row>
<entry><type>any</></entry>
- <entry>Indicates that a function accepts any input datatype whatever</entry>
+ <entry>Indicates that a function accepts any input data type whatever</entry>
</row>
<row>
<entry><type>anyarray</></entry>
- <entry>Indicates that a function accepts any array datatype</entry>
+ <entry>Indicates that a function accepts any array data type</entry>
</row>
<row>
<para>
Functions coded in C (whether built-in or dynamically loaded) may be
- declared to accept or return any of these pseudo datatypes. It is up to
+ declared to accept or return any of these pseudo data types. It is up to
the function author to ensure that the function will behave safely
when a pseudo-type is used as an argument type.
</para>
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ddl.sgml,v 1.4 2002/09/12 22:05:35 petere Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ddl.sgml,v 1.5 2002/09/21 18:32:52 petere Exp $ -->
<chapter id="ddl">
<title>Data Definition</title>
Note that these do not excuse you from observing any constraints.
For example, if an action specifies <literal>SET DEFAULT</literal>
but the default value would not satisfy the foreign key, the
- deletion of the primary key wil fail.
+ deletion of the primary key will fail.
</para>
<para>
</para>
<para>
- The first schema in the seach path that exists is the default
+ The first schema in the search path that exists is the default
location for creating new objects. That is the reason that by
default objects are created in the public schema. When objects
are referenced in any other context without schema qualification
</para>
<para>
- The search path works in the same way for datatype names, function names,
- and operator names as it does for table names. Datatype and function
+ The search path works in the same way for data type names, function names,
+ and operator names as it does for table names. Data type and function
names can be qualified in exactly the same way as table names. If you
need to write a qualified operator name in an expression, there is a
special provision: you must write
<para>
In addition to <literal>public</> and user-created schemas, each
database contains a <literal>pg_catalog</> schema, which contains
- the system tables and all the built-in datatypes, functions, and
+ the system tables and all the built-in data types, functions, and
operators. <literal>pg_catalog</> is always effectively part of
the search path. If it is not named explicitly in the path then
it is implicitly searched <emphasis>before</> searching the path's
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/Attic/developer.sgml,v 1.6 2001/10/09 18:45:59 petere Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/Attic/developer.sgml,v 1.7 2002/09/21 18:32:52 petere Exp $ -->
<!-- PostgreSQL Developer's Guide -->
<book id="developer">
</bookinfo>
&sources;
- &arch-dev;
+ &arch-dev;
&catalogs;
&protocol;
&compiler;
&bki;
&page;
&geqo;
+ &gist;
&nls;
<!-- appendices -->
&cvs;
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/dfunc.sgml,v 1.21 2002/08/26 23:22:47 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/dfunc.sgml,v 1.22 2002/09/21 18:32:52 petere Exp $
-->
<sect2 id="dfunc">
<variablelist>
<varlistentry>
- <term><productname>BSD/OS</productname></term>
+ <term><systemitem class="osname">BSD/OS</></term>
<indexterm><primary>BSD/OS</></>
<listitem>
<para>
ld -shared -o foo.so foo.o
</programlisting>
This is applicable as of version 4.0 of
- <productname>BSD/OS</productname>.
+ <systemitem class="osname">BSD/OS</>.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><productname>FreeBSD</productname></term>
+ <term><systemitem class="osname">FreeBSD</></term>
<indexterm><primary>FreeBSD</></>
<listitem>
<para>
gcc -shared -o foo.so foo.o
</programlisting>
This is applicable as of version 3.0 of
- <productname>FreeBSD</productname>.
+ <systemitem class="osname">FreeBSD</>.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term><productname>HP-UX</productname></term>
+ <term><systemitem class="osname">HP-UX</></term>
<indexterm><primary>HP-UX</></>
<listitem>
<para>
The compiler flag of the system compiler to create
<acronym>PIC</acronym> is <option>+z</option>. When using
- <productname>GCC</productname> it's <option>-fpic</option>. The
+ <application>GCC</application> it's <option>-fpic</option>. The
linker flag for shared libraries is <option>-b</option>. So
<programlisting>
cc +z -c foo.c
<programlisting>
ld -b -o foo.sl foo.o
</programlisting>
- <productname>HP-UX</productname> uses the extension
+ <systemitem class="osname">HP-UX</> uses the extension
<filename>.sl</filename> for shared libraries, unlike most other
systems.
</para>
</varlistentry>
<varlistentry>
- <term><productname>IRIX</productname></term>
+ <term><systemitem class="osname">IRIX</></term>
<indexterm><primary>IRIX</></>
<listitem>
<para>
</varlistentry>
<varlistentry>
- <term><productname>Linux</productname></term>
+ <term><systemitem class="osname">Linux</></term>
<indexterm><primary>Linux</></>
<listitem>
<para>
</varlistentry>
<varlistentry>
- <term><productname>NetBSD</productname></term>
+ <term><systemitem class="osname">MacOS X</></term>
+ <indexterm><primary>MacOS X</></>
+ <listitem>
+ <para>
+ Here is a sample. It assumes the developer tools are installed.
+<programlisting>
+cc -c foo.c
+cc -bundle -flat_namespace -undefined suppress -o foo.so foo.o
+</programlisting>
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><systemitem class="osname">NetBSD</></term>
<indexterm><primary>NetBSD</></>
<listitem>
<para>
</varlistentry>
<varlistentry>
- <term><productname>OpenBSD</productname></term>
+ <term><systemitem class="osname">OpenBSD</></term>
<indexterm><primary>OpenBSD</></>
<listitem>
<para>
</varlistentry>
<varlistentry>
- <term><productname>OS X</productname></term>
- <indexterm><primary>OS X</></>
- <listitem>
- <para>
- Here is a sample. It assumes the developer tools are installed.
-<programlisting>
-cc -c foo.c
-cc -bundle -flat_namespace -undefined suppress -o foo.so foo.o
-</programlisting>
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><productname>Solaris</productname></term>
+ <term><systemitem class="osname">Solaris</></term>
<indexterm><primary>Solaris</></>
<listitem>
<para>
The compiler flag to create <acronym>PIC</acronym> is
<option>-KPIC</option> with the Sun compiler and
- <option>-fpic</option> with <productname>GCC</productname>. To
+ <option>-fpic</option> with <application>GCC</>. To
link shared libraries, the compiler option is
<option>-G</option> with either compiler or alternatively
- <option>-shared</option> with <productname>GCC</productname>.
+ <option>-shared</option> with <application>GCC</>.
<programlisting>
cc -KPIC -c foo.c
cc -G -o foo.so foo.o
</varlistentry>
<varlistentry>
- <term>Tru64 UNIX</term>
+ <term><systemitem class="osname">Tru64 UNIX</></term>
<indexterm><primary>Tru64 UNIX</></>
<indexterm><primary>Digital UNIX</><see>Tru64 UNIX</></>
<listitem>
</varlistentry>
<varlistentry>
- <term><productname>UnixWare</productname></term>
+ <term><systemitem class="osname">UnixWare</></term>
<indexterm><primary>UnixWare</></>
<listitem>
<para>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/diskusage.sgml,v 1.4 2002/07/05 00:14:16 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/diskusage.sgml,v 1.5 2002/09/21 18:32:52 petere Exp $
-->
<chapter id="diskusage">
Each table has a primary heap disk file where most of the data is
stored. To store long column values, there is also a
<acronym>TOAST</> file associated with the table, named based on the
- table's oid (actually pg_class.relfilenode), and an index on the
+ table's OID (actually <literal>pg_class.relfilenode</>), and an index on the
<acronym>TOAST</> table. There also may be indexes associated with
the base table.
</para>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ecpg.sgml,v 1.36 2002/01/20 22:19:55 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ecpg.sgml,v 1.37 2002/09/21 18:32:52 petere Exp $
-->
<chapter id="ecpg">
<programlisting>
exec sql include sqlca;
</programlisting>
- in the include section of your file. This will define a struct and
- a variable with the name <parameter>sqlca</parameter> as follows:
+ in the include section of your file. This will define a <type>struct</> and
+ a variable with the name <varname>sqlca</varname> as follows:
<programlisting>
struct sqlca
{
<para>
If an no error occurred in the last <acronym>SQL</acronym> statement.
- <parameter>sqlca.sqlcode</parameter> will be 0 (ECPG_NO_ERROR). If
+ <parameter>sqlca.sqlcode</parameter> will be 0 (<symbol>ECPG_NO_ERROR</>). If
<parameter>sqlca.sqlcode</parameter> is less that zero, this is a
serious error, like the database definition does not match the
query. If it is greater than zero, it is a normal error like the
</para>
<para>
- The special types <type>VARCHAR</type> and <type>VARCHAR2</type> are converted into a named struct
- for every variable. A declaration like:
+ The special types <type>VARCHAR</type> and
+ <type>VARCHAR2</type> are converted into a named <type>struct</> for
+ every variable. A declaration like:
<programlisting>
VARCHAR var[180];
</programlisting>
</varlistentry>
<varlistentry>
- <term><literal>ECPGt_EOIT</literal></term>
+ <term><parameter>ECPGt_EOIT</></term>
<listitem>
<para>
- An enum telling that there are no more input variables.
+ An <type>enum</> telling that there are no more input variables.
</para>
</listitem>
</varlistentry>
</varlistentry>
<varlistentry>
- <term>ECPGt_EORT</term>
+ <term><parameter>ECPGt_EORT</></term>
<listitem>
<para>
- An enum telling that there are no more variables.
+ An <type>enum</> telling that there are no more variables.
</para>
</listitem>
</varlistentry>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/extend.sgml,v 1.16 2002/07/30 17:34:37 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/extend.sgml,v 1.17 2002/09/21 18:32:53 petere Exp $
-->
<chapter id="extend">
</thead>
<tbody>
<row>
- <entry>pg_database</entry>
+ <entry><structname>pg_database</></entry>
<entry> databases</entry>
</row>
<row>
- <entry>pg_class</entry>
+ <entry><structname>pg_class</></entry>
<entry> tables</entry>
</row>
<row>
- <entry>pg_attribute</entry>
+ <entry><structname>pg_attribute</></entry>
<entry> table columns</entry>
</row>
<row>
- <entry>pg_index</entry>
+ <entry><structname>pg_index</></entry>
<entry> indexes</entry>
</row>
<row>
- <entry>pg_proc</entry>
+ <entry><structname>pg_proc</></entry>
<entry> procedures/functions </entry>
</row>
<row>
- <entry>pg_type</entry>
+ <entry><structname>pg_type</></entry>
<entry> data types (both base and complex)</entry>
</row>
<row>
- <entry>pg_operator</entry>
+ <entry><structname>pg_operator</></entry>
<entry> operators</entry>
</row>
<row>
- <entry>pg_aggregate</entry>
+ <entry><structname>pg_aggregate</></entry>
<entry> aggregate functions</entry>
</row>
<row>
- <entry>pg_am</entry>
+ <entry><structname>pg_am</></entry>
<entry> access methods</entry>
</row>
<row>
- <entry>pg_amop</entry>
+ <entry><structname>pg_amop</></entry>
<entry> access method operators</entry>
</row>
<row>
- <entry>pg_amproc</entry>
+ <entry><structname>pg_amproc</></entry>
<entry> access method support functions</entry>
</row>
<row>
- <entry>pg_opclass</entry>
+ <entry><structname>pg_opclass</></entry>
<entry> access method operator classes</entry>
</row>
</tbody>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/features.sgml,v 2.6 2002/08/04 06:17:29 thomas Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/features.sgml,v 2.7 2002/09/21 18:32:53 petere Exp $
-->
<appendix id="features">
</row>
<row>
<entry>F831-01</entry>
- <entry>Updateable scrollable cursors</entry>
+ <entry>Updatable scrollable cursors</entry>
<entry></entry>
</row>
<row>
<entry>F831-02</entry>
- <entry>Updateable ordered cursors</entry>
+ <entry>Updatable ordered cursors</entry>
<entry></entry>
</row>
<row>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/func.sgml,v 1.123 2002/09/20 03:44:06 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/func.sgml,v 1.124 2002/09/21 18:32:53 petere Exp $
PostgreSQL documentation
-->
<member>NOT</member>
</simplelist>
- <acronym>SQL</acronym> uses a three-valued Boolean logic where NULL represents
+ <acronym>SQL</acronym> uses a three-valued Boolean logic where the null value represents
<quote>unknown</quote>. Observe the following truth tables:
<informaltable>
</para>
<para>
- To check whether a value is or is not NULL, use the constructs
+ To check whether a value is or is not null, use the constructs
<synopsis>
<replaceable>expression</replaceable> IS NULL
<replaceable>expression</replaceable> IS NOT NULL
<para>
Do <emphasis>not</emphasis> write
<literal><replaceable>expression</replaceable> = NULL</literal>
- because NULL is not <quote>equal to</quote> NULL. (NULL represents
- an unknown value, and it is not known whether two unknown values are
- equal.)
+ because <literal>NULL</> is not <quote>equal to</quote>
+ <literal>NULL</>. (The null value represents an unknown value,
+ and it is not known whether two unknown values are equal.)
</para>
<para>
Some applications may (incorrectly) require that
<literal><replaceable>expression</replaceable> = NULL</literal>
returns true if <replaceable>expression</replaceable> evaluates to
- the NULL value. To support these applications, the run-time option
+ the null value. To support these applications, the run-time option
<varname>transform_null_equals</varname> can be turned on (e.g.,
<literal>SET transform_null_equals TO ON;</literal>).
<productname>PostgreSQL</productname> will then convert
<replaceable>expression</replaceable> IS NOT UNKNOWN
</synopsis>
These are similar to <literal>IS NULL</literal> in that they will
- always return TRUE or FALSE, never NULL, even when the operand is NULL.
- A NULL input is treated as the logical value UNKNOWN.
+ always return true or false, never a null value, even when the operand is null.
+ A null input is treated as the logical value <quote>unknown</>.
</para>
</sect1>
<tbody>
<row>
- <entry>ascii_to_mic</entry>
- <entry>SQL_ASCII</entry>
- <entry>MULE_INTERNAL</entry>
+ <entry><literal>ascii_to_mic</literal></entry>
+ <entry><literal>SQL_ASCII</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
</row>
<row>
- <entry>ascii_to_utf_8</entry>
- <entry>SQL_ASCII</entry>
- <entry>UNICODE</entry>
+ <entry><literal>ascii_to_utf_8</literal></entry>
+ <entry><literal>SQL_ASCII</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>big5_to_euc_tw</entry>
- <entry>BIG5</entry>
- <entry>EUC_TW</entry>
+ <entry><literal>big5_to_euc_tw</literal></entry>
+ <entry><literal>BIG5</literal></entry>
+ <entry><literal>EUC_TW</literal></entry>
</row>
<row>
- <entry>big5_to_mic</entry>
- <entry>BIG5</entry>
- <entry>MULE_INTERNAL</entry>
+ <entry><literal>big5_to_mic</literal></entry>
+ <entry><literal>BIG5</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
</row>
<row>
- <entry>big5_to_utf_8</entry>
- <entry>BIG5</entry>
- <entry>UNICODE</entry>
+ <entry><literal>big5_to_utf_8</literal></entry>
+ <entry><literal>BIG5</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>euc_cn_to_mic</entry>
- <entry>EUC_CN</entry>
- <entry>MULE_INTERNAL</entry>
+ <entry><literal>euc_cn_to_mic</literal></entry>
+ <entry><literal>EUC_CN</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
</row>
<row>
- <entry>euc_cn_to_utf_8</entry>
- <entry>EUC_CN</entry>
- <entry>UNICODE</entry>
+ <entry><literal>euc_cn_to_utf_8</literal></entry>
+ <entry><literal>EUC_CN</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>euc_jp_to_mic</entry>
- <entry>EUC_JP</entry>
- <entry>MULE_INTERNAL</entry>
+ <entry><literal>euc_jp_to_mic</literal></entry>
+ <entry><literal>EUC_JP</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
</row>
<row>
- <entry>euc_jp_to_sjis</entry>
- <entry>EUC_JP</entry>
- <entry>SJIS</entry>
+ <entry><literal>euc_jp_to_sjis</literal></entry>
+ <entry><literal>EUC_JP</literal></entry>
+ <entry><literal>SJIS</literal></entry>
</row>
<row>
- <entry>euc_jp_to_utf_8</entry>
- <entry>EUC_JP</entry>
- <entry>UNICODE</entry>
+ <entry><literal>euc_jp_to_utf_8</literal></entry>
+ <entry><literal>EUC_JP</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>euc_kr_to_mic</entry>
- <entry>EUC_KR</entry>
- <entry>MULE_INTERNAL</entry>
+ <entry><literal>euc_kr_to_mic</literal></entry>
+ <entry><literal>EUC_KR</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
</row>
<row>
- <entry>euc_kr_to_utf_8</entry>
- <entry>EUC_KR</entry>
- <entry>UNICODE</entry>
+ <entry><literal>euc_kr_to_utf_8</literal></entry>
+ <entry><literal>EUC_KR</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>euc_tw_to_big5</entry>
- <entry>EUC_TW</entry>
- <entry>BIG5</entry>
+ <entry><literal>euc_tw_to_big5</literal></entry>
+ <entry><literal>EUC_TW</literal></entry>
+ <entry><literal>BIG5</literal></entry>
</row>
<row>
- <entry>euc_tw_to_mic</entry>
- <entry>EUC_TW</entry>
- <entry>MULE_INTERNAL</entry>
+ <entry><literal>euc_tw_to_mic</literal></entry>
+ <entry><literal>EUC_TW</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
</row>
<row>
- <entry>euc_tw_to_utf_8</entry>
- <entry>EUC_TW</entry>
- <entry>UNICODE</entry>
+ <entry><literal>euc_tw_to_utf_8</literal></entry>
+ <entry><literal>EUC_TW</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>gb18030_to_utf_8</entry>
- <entry>GB18030</entry>
- <entry>UNICODE</entry>
+ <entry><literal>gb18030_to_utf_8</literal></entry>
+ <entry><literal>GB18030</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>gbk_to_utf_8</entry>
- <entry>GBK</entry>
- <entry>UNICODE</entry>
+ <entry><literal>gbk_to_utf_8</literal></entry>
+ <entry><literal>GBK</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>iso_8859_10_to_utf_8</entry>
- <entry>LATIN6</entry>
- <entry>UNICODE</entry>
+ <entry><literal>iso_8859_10_to_utf_8</literal></entry>
+ <entry><literal>LATIN6</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>iso_8859_13_to_utf_8</entry>
- <entry>LATIN7</entry>
- <entry>UNICODE</entry>
+ <entry><literal>iso_8859_13_to_utf_8</literal></entry>
+ <entry><literal>LATIN7</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>iso_8859_14_to_utf_8</entry>
- <entry>LATIN8</entry>
- <entry>UNICODE</entry>
+ <entry><literal>iso_8859_14_to_utf_8</literal></entry>
+ <entry><literal>LATIN8</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>iso_8859_15_to_utf_8</entry>
- <entry>LATIN9</entry>
- <entry>UNICODE</entry>
+ <entry><literal>iso_8859_15_to_utf_8</literal></entry>
+ <entry><literal>LATIN9</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>iso_8859_16_to_utf_8</entry>
- <entry>LATIN10</entry>
- <entry>UNICODE</entry>
+ <entry><literal>iso_8859_16_to_utf_8</literal></entry>
+ <entry><literal>LATIN10</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>iso_8859_1_to_mic</entry>
- <entry>LATIN1</entry>
- <entry>MULE_INTERNAL</entry>
+ <entry><literal>iso_8859_1_to_mic</literal></entry>
+ <entry><literal>LATIN1</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
</row>
<row>
- <entry>iso_8859_1_to_utf_8</entry>
- <entry>LATIN1</entry>
- <entry>UNICODE</entry>
+ <entry><literal>iso_8859_1_to_utf_8</literal></entry>
+ <entry><literal>LATIN1</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>iso_8859_2_to_mic</entry>
- <entry>LATIN2</entry>
- <entry>MULE_INTERNAL</entry>
+ <entry><literal>iso_8859_2_to_mic</literal></entry>
+ <entry><literal>LATIN2</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
</row>
<row>
- <entry>iso_8859_2_to_utf_8</entry>
- <entry>LATIN2</entry>
- <entry>UNICODE</entry>
+ <entry><literal>iso_8859_2_to_utf_8</literal></entry>
+ <entry><literal>LATIN2</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>iso_8859_2_to_win1250</entry>
- <entry>LATIN2</entry>
- <entry>WIN1250</entry>
+ <entry><literal>iso_8859_2_to_win1250</literal></entry>
+ <entry><literal>LATIN2</literal></entry>
+ <entry><literal>WIN1250</literal></entry>
</row>
<row>
- <entry>iso_8859_3_to_mic</entry>
- <entry>LATIN3</entry>
- <entry>MULE_INTERNAL</entry>
+ <entry><literal>iso_8859_3_to_mic</literal></entry>
+ <entry><literal>LATIN3</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
</row>
<row>
- <entry>iso_8859_3_to_utf_8</entry>
- <entry>LATIN3</entry>
- <entry>UNICODE</entry>
+ <entry><literal>iso_8859_3_to_utf_8</literal></entry>
+ <entry><literal>LATIN3</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>iso_8859_4_to_mic</entry>
- <entry>LATIN4</entry>
- <entry>MULE_INTERNAL</entry>
+ <entry><literal>iso_8859_4_to_mic</literal></entry>
+ <entry><literal>LATIN4</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
</row>
<row>
- <entry>iso_8859_4_to_utf_8</entry>
- <entry>LATIN4</entry>
- <entry>UNICODE</entry>
+ <entry><literal>iso_8859_4_to_utf_8</literal></entry>
+ <entry><literal>LATIN4</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>iso_8859_5_to_koi8r</entry>
- <entry>ISO_8859_5</entry>
- <entry>KOI8</entry>
+ <entry><literal>iso_8859_5_to_koi8r</literal></entry>
+ <entry><literal>ISO_8859_5</literal></entry>
+ <entry><literal>KOI8</literal></entry>
</row>
<row>
- <entry>iso_8859_5_to_mic</entry>
- <entry>ISO_8859_5</entry>
- <entry>MULE_INTERNAL</entry>
+ <entry><literal>iso_8859_5_to_mic</literal></entry>
+ <entry><literal>ISO_8859_5</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
</row>
<row>
- <entry>iso_8859_5_to_utf_8</entry>
- <entry>ISO_8859_5</entry>
- <entry>UNICODE</entry>
+ <entry><literal>iso_8859_5_to_utf_8</literal></entry>
+ <entry><literal>ISO_8859_5</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>iso_8859_5_to_win1251</entry>
- <entry>ISO_8859_5</entry>
- <entry>WIN</entry>
+ <entry><literal>iso_8859_5_to_win1251</literal></entry>
+ <entry><literal>ISO_8859_5</literal></entry>
+ <entry><literal>WIN</literal></entry>
</row>
<row>
- <entry>iso_8859_5_to_win866</entry>
- <entry>ISO_8859_5</entry>
- <entry>ALT</entry>
+ <entry><literal>iso_8859_5_to_win866</literal></entry>
+ <entry><literal>ISO_8859_5</literal></entry>
+ <entry><literal>ALT</literal></entry>
</row>
<row>
- <entry>iso_8859_6_to_utf_8</entry>
- <entry>ISO_8859_6</entry>
- <entry>UNICODE</entry>
+ <entry><literal>iso_8859_6_to_utf_8</literal></entry>
+ <entry><literal>ISO_8859_6</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>iso_8859_7_to_utf_8</entry>
- <entry>ISO_8859_7</entry>
- <entry>UNICODE</entry>
+ <entry><literal>iso_8859_7_to_utf_8</literal></entry>
+ <entry><literal>ISO_8859_7</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>iso_8859_8_to_utf_8</entry>
- <entry>ISO_8859_8</entry>
- <entry>UNICODE</entry>
+ <entry><literal>iso_8859_8_to_utf_8</literal></entry>
+ <entry><literal>ISO_8859_8</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>iso_8859_9_to_utf_8</entry>
- <entry>LATIN5</entry>
- <entry>UNICODE</entry>
+ <entry><literal>iso_8859_9_to_utf_8</literal></entry>
+ <entry><literal>LATIN5</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>johab_to_utf_8</entry>
- <entry>JOHAB</entry>
- <entry>UNICODE</entry>
+ <entry><literal>johab_to_utf_8</literal></entry>
+ <entry><literal>JOHAB</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>koi8r_to_iso_8859_5</entry>
- <entry>KOI8</entry>
- <entry>ISO_8859_5</entry>
+ <entry><literal>koi8r_to_iso_8859_5</literal></entry>
+ <entry><literal>KOI8</literal></entry>
+ <entry><literal>ISO_8859_5</literal></entry>
</row>
<row>
- <entry>koi8r_to_mic</entry>
- <entry>KOI8</entry>
- <entry>MULE_INTERNAL</entry>
+ <entry><literal>koi8r_to_mic</literal></entry>
+ <entry><literal>KOI8</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
</row>
<row>
- <entry>koi8r_to_utf_8</entry>
- <entry>KOI8</entry>
- <entry>UNICODE</entry>
+ <entry><literal>koi8r_to_utf_8</literal></entry>
+ <entry><literal>KOI8</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>koi8r_to_win1251</entry>
- <entry>KOI8</entry>
- <entry>WIN</entry>
+ <entry><literal>koi8r_to_win1251</literal></entry>
+ <entry><literal>KOI8</literal></entry>
+ <entry><literal>WIN</literal></entry>
</row>
<row>
- <entry>koi8r_to_win866</entry>
- <entry>KOI8</entry>
- <entry>ALT</entry>
+ <entry><literal>koi8r_to_win866</literal></entry>
+ <entry><literal>KOI8</literal></entry>
+ <entry><literal>ALT</literal></entry>
</row>
<row>
- <entry>mic_to_ascii</entry>
- <entry>MULE_INTERNAL</entry>
- <entry>SQL_ASCII</entry>
+ <entry><literal>mic_to_ascii</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
+ <entry><literal>SQL_ASCII</literal></entry>
</row>
<row>
- <entry>mic_to_big5</entry>
- <entry>MULE_INTERNAL</entry>
- <entry>BIG5</entry>
+ <entry><literal>mic_to_big5</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
+ <entry><literal>BIG5</literal></entry>
</row>
<row>
- <entry>mic_to_euc_cn</entry>
- <entry>MULE_INTERNAL</entry>
- <entry>EUC_CN</entry>
+ <entry><literal>mic_to_euc_cn</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
+ <entry><literal>EUC_CN</literal></entry>
</row>
<row>
- <entry>mic_to_euc_jp</entry>
- <entry>MULE_INTERNAL</entry>
- <entry>EUC_JP</entry>
+ <entry><literal>mic_to_euc_jp</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
+ <entry><literal>EUC_JP</literal></entry>
</row>
<row>
- <entry>mic_to_euc_kr</entry>
- <entry>MULE_INTERNAL</entry>
- <entry>EUC_KR</entry>
+ <entry><literal>mic_to_euc_kr</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
+ <entry><literal>EUC_KR</literal></entry>
</row>
<row>
- <entry>mic_to_euc_tw</entry>
- <entry>MULE_INTERNAL</entry>
- <entry>EUC_TW</entry>
+ <entry><literal>mic_to_euc_tw</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
+ <entry><literal>EUC_TW</literal></entry>
</row>
<row>
- <entry>mic_to_iso_8859_1</entry>
- <entry>MULE_INTERNAL</entry>
- <entry>LATIN1</entry>
+ <entry><literal>mic_to_iso_8859_1</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
+ <entry><literal>LATIN1</literal></entry>
</row>
<row>
- <entry>mic_to_iso_8859_2</entry>
- <entry>MULE_INTERNAL</entry>
- <entry>LATIN2</entry>
+ <entry><literal>mic_to_iso_8859_2</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
+ <entry><literal>LATIN2</literal></entry>
</row>
<row>
- <entry>mic_to_iso_8859_3</entry>
- <entry>MULE_INTERNAL</entry>
- <entry>LATIN3</entry>
+ <entry><literal>mic_to_iso_8859_3</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
+ <entry><literal>LATIN3</literal></entry>
</row>
<row>
- <entry>mic_to_iso_8859_4</entry>
- <entry>MULE_INTERNAL</entry>
- <entry>LATIN4</entry>
+ <entry><literal>mic_to_iso_8859_4</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
+ <entry><literal>LATIN4</literal></entry>
</row>
<row>
- <entry>mic_to_iso_8859_5</entry>
- <entry>MULE_INTERNAL</entry>
- <entry>ISO_8859_5</entry>
+ <entry><literal>mic_to_iso_8859_5</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
+ <entry><literal>ISO_8859_5</literal></entry>
</row>
<row>
- <entry>mic_to_koi8r</entry>
- <entry>MULE_INTERNAL</entry>
- <entry>KOI8</entry>
+ <entry><literal>mic_to_koi8r</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
+ <entry><literal>KOI8</literal></entry>
</row>
<row>
- <entry>mic_to_sjis</entry>
- <entry>MULE_INTERNAL</entry>
- <entry>SJIS</entry>
+ <entry><literal>mic_to_sjis</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
+ <entry><literal>SJIS</literal></entry>
</row>
<row>
- <entry>mic_to_win1250</entry>
- <entry>MULE_INTERNAL</entry>
- <entry>WIN1250</entry>
+ <entry><literal>mic_to_win1250</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
+ <entry><literal>WIN1250</literal></entry>
</row>
<row>
- <entry>mic_to_win1251</entry>
- <entry>MULE_INTERNAL</entry>
- <entry>WIN</entry>
+ <entry><literal>mic_to_win1251</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
+ <entry><literal>WIN</literal></entry>
</row>
<row>
- <entry>mic_to_win866</entry>
- <entry>MULE_INTERNAL</entry>
- <entry>ALT</entry>
+ <entry><literal>mic_to_win866</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
+ <entry><literal>ALT</literal></entry>
</row>
<row>
- <entry>sjis_to_euc_jp</entry>
- <entry>SJIS</entry>
- <entry>EUC_JP</entry>
+ <entry><literal>sjis_to_euc_jp</literal></entry>
+ <entry><literal>SJIS</literal></entry>
+ <entry><literal>EUC_JP</literal></entry>
</row>
<row>
- <entry>sjis_to_mic</entry>
- <entry>SJIS</entry>
- <entry>MULE_INTERNAL</entry>
+ <entry><literal>sjis_to_mic</literal></entry>
+ <entry><literal>SJIS</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
</row>
<row>
- <entry>sjis_to_utf_8</entry>
- <entry>SJIS</entry>
- <entry>UNICODE</entry>
+ <entry><literal>sjis_to_utf_8</literal></entry>
+ <entry><literal>SJIS</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>tcvn_to_utf_8</entry>
- <entry>TCVN</entry>
- <entry>UNICODE</entry>
+ <entry><literal>tcvn_to_utf_8</literal></entry>
+ <entry><literal>TCVN</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>uhc_to_utf_8</entry>
- <entry>UHC</entry>
- <entry>UNICODE</entry>
+ <entry><literal>uhc_to_utf_8</literal></entry>
+ <entry><literal>UHC</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>utf_8_to_ascii</entry>
- <entry>UNICODE</entry>
- <entry>SQL_ASCII</entry>
+ <entry><literal>utf_8_to_ascii</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>SQL_ASCII</literal></entry>
</row>
<row>
- <entry>utf_8_to_big5</entry>
- <entry>UNICODE</entry>
- <entry>BIG5</entry>
+ <entry><literal>utf_8_to_big5</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>BIG5</literal></entry>
</row>
<row>
- <entry>utf_8_to_euc_cn</entry>
- <entry>UNICODE</entry>
- <entry>EUC_CN</entry>
+ <entry><literal>utf_8_to_euc_cn</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>EUC_CN</literal></entry>
</row>
<row>
- <entry>utf_8_to_euc_jp</entry>
- <entry>UNICODE</entry>
- <entry>EUC_JP</entry>
+ <entry><literal>utf_8_to_euc_jp</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>EUC_JP</literal></entry>
</row>
<row>
- <entry>utf_8_to_euc_kr</entry>
- <entry>UNICODE</entry>
- <entry>EUC_KR</entry>
+ <entry><literal>utf_8_to_euc_kr</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>EUC_KR</literal></entry>
</row>
<row>
- <entry>utf_8_to_euc_tw</entry>
- <entry>UNICODE</entry>
- <entry>EUC_TW</entry>
+ <entry><literal>utf_8_to_euc_tw</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>EUC_TW</literal></entry>
</row>
<row>
- <entry>utf_8_to_gb18030</entry>
- <entry>UNICODE</entry>
- <entry>GB18030</entry>
+ <entry><literal>utf_8_to_gb18030</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>GB18030</literal></entry>
</row>
<row>
- <entry>utf_8_to_gbk</entry>
- <entry>UNICODE</entry>
- <entry>GBK</entry>
+ <entry><literal>utf_8_to_gbk</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>GBK</literal></entry>
</row>
<row>
- <entry>utf_8_to_iso_8859_1</entry>
- <entry>UNICODE</entry>
- <entry>LATIN1</entry>
+ <entry><literal>utf_8_to_iso_8859_1</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>LATIN1</literal></entry>
</row>
<row>
- <entry>utf_8_to_iso_8859_10</entry>
- <entry>UNICODE</entry>
- <entry>LATIN6</entry>
+ <entry><literal>utf_8_to_iso_8859_10</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>LATIN6</literal></entry>
</row>
<row>
- <entry>utf_8_to_iso_8859_13</entry>
- <entry>UNICODE</entry>
- <entry>LATIN7</entry>
+ <entry><literal>utf_8_to_iso_8859_13</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>LATIN7</literal></entry>
</row>
<row>
- <entry>utf_8_to_iso_8859_14</entry>
- <entry>UNICODE</entry>
- <entry>LATIN8</entry>
+ <entry><literal>utf_8_to_iso_8859_14</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>LATIN8</literal></entry>
</row>
<row>
- <entry>utf_8_to_iso_8859_15</entry>
- <entry>UNICODE</entry>
- <entry>LATIN9</entry>
+ <entry><literal>utf_8_to_iso_8859_15</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>LATIN9</literal></entry>
</row>
<row>
- <entry>utf_8_to_iso_8859_16</entry>
- <entry>UNICODE</entry>
- <entry>LATIN10</entry>
+ <entry><literal>utf_8_to_iso_8859_16</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>LATIN10</literal></entry>
</row>
<row>
- <entry>utf_8_to_iso_8859_2</entry>
- <entry>UNICODE</entry>
- <entry>LATIN2</entry>
+ <entry><literal>utf_8_to_iso_8859_2</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>LATIN2</literal></entry>
</row>
<row>
- <entry>utf_8_to_iso_8859_3</entry>
- <entry>UNICODE</entry>
- <entry>LATIN3</entry>
+ <entry><literal>utf_8_to_iso_8859_3</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>LATIN3</literal></entry>
</row>
<row>
- <entry>utf_8_to_iso_8859_4</entry>
- <entry>UNICODE</entry>
- <entry>LATIN4</entry>
+ <entry><literal>utf_8_to_iso_8859_4</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>LATIN4</literal></entry>
</row>
<row>
- <entry>utf_8_to_iso_8859_5</entry>
- <entry>UNICODE</entry>
- <entry>ISO_8859_5</entry>
+ <entry><literal>utf_8_to_iso_8859_5</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>ISO_8859_5</literal></entry>
</row>
<row>
- <entry>utf_8_to_iso_8859_6</entry>
- <entry>UNICODE</entry>
- <entry>ISO_8859_6</entry>
+ <entry><literal>utf_8_to_iso_8859_6</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>ISO_8859_6</literal></entry>
</row>
<row>
- <entry>utf_8_to_iso_8859_7</entry>
- <entry>UNICODE</entry>
- <entry>ISO_8859_7</entry>
+ <entry><literal>utf_8_to_iso_8859_7</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>ISO_8859_7</literal></entry>
</row>
<row>
- <entry>utf_8_to_iso_8859_8</entry>
- <entry>UNICODE</entry>
- <entry>ISO_8859_8</entry>
+ <entry><literal>utf_8_to_iso_8859_8</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>ISO_8859_8</literal></entry>
</row>
<row>
- <entry>utf_8_to_iso_8859_9</entry>
- <entry>UNICODE</entry>
- <entry>LATIN5</entry>
+ <entry><literal>utf_8_to_iso_8859_9</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>LATIN5</literal></entry>
</row>
<row>
- <entry>utf_8_to_johab</entry>
- <entry>UNICODE</entry>
- <entry>JOHAB</entry>
+ <entry><literal>utf_8_to_johab</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>JOHAB</literal></entry>
</row>
<row>
- <entry>utf_8_to_koi8r</entry>
- <entry>UNICODE</entry>
- <entry>KOI8</entry>
+ <entry><literal>utf_8_to_koi8r</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>KOI8</literal></entry>
</row>
<row>
- <entry>utf_8_to_sjis</entry>
- <entry>UNICODE</entry>
- <entry>SJIS</entry>
+ <entry><literal>utf_8_to_sjis</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>SJIS</literal></entry>
</row>
<row>
- <entry>utf_8_to_tcvn</entry>
- <entry>UNICODE</entry>
- <entry>TCVN</entry>
+ <entry><literal>utf_8_to_tcvn</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>TCVN</literal></entry>
</row>
<row>
- <entry>utf_8_to_uhc</entry>
- <entry>UNICODE</entry>
- <entry>UHC</entry>
+ <entry><literal>utf_8_to_uhc</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>UHC</literal></entry>
</row>
<row>
- <entry>utf_8_to_win1250</entry>
- <entry>UNICODE</entry>
- <entry>WIN1250</entry>
+ <entry><literal>utf_8_to_win1250</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>WIN1250</literal></entry>
</row>
<row>
- <entry>utf_8_to_win1251</entry>
- <entry>UNICODE</entry>
- <entry>WIN</entry>
+ <entry><literal>utf_8_to_win1251</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>WIN</literal></entry>
</row>
<row>
- <entry>utf_8_to_win1256</entry>
- <entry>UNICODE</entry>
- <entry>WIN1256</entry>
+ <entry><literal>utf_8_to_win1256</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>WIN1256</literal></entry>
</row>
<row>
- <entry>utf_8_to_win866</entry>
- <entry>UNICODE</entry>
- <entry>ALT</entry>
+ <entry><literal>utf_8_to_win866</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>ALT</literal></entry>
</row>
<row>
- <entry>utf_8_to_win874</entry>
- <entry>UNICODE</entry>
- <entry>WIN874</entry>
+ <entry><literal>utf_8_to_win874</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
+ <entry><literal>WIN874</literal></entry>
</row>
<row>
- <entry>win1250_to_iso_8859_2</entry>
- <entry>WIN1250</entry>
- <entry>LATIN2</entry>
+ <entry><literal>win1250_to_iso_8859_2</literal></entry>
+ <entry><literal>WIN1250</literal></entry>
+ <entry><literal>LATIN2</literal></entry>
</row>
<row>
- <entry>win1250_to_mic</entry>
- <entry>WIN1250</entry>
- <entry>MULE_INTERNAL</entry>
+ <entry><literal>win1250_to_mic</literal></entry>
+ <entry><literal>WIN1250</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
</row>
<row>
- <entry>win1250_to_utf_8</entry>
- <entry>WIN1250</entry>
- <entry>UNICODE</entry>
+ <entry><literal>win1250_to_utf_8</literal></entry>
+ <entry><literal>WIN1250</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>win1251_to_iso_8859_5</entry>
- <entry>WIN</entry>
- <entry>ISO_8859_5</entry>
+ <entry><literal>win1251_to_iso_8859_5</literal></entry>
+ <entry><literal>WIN</literal></entry>
+ <entry><literal>ISO_8859_5</literal></entry>
</row>
<row>
- <entry>win1251_to_koi8r</entry>
- <entry>WIN</entry>
- <entry>KOI8</entry>
+ <entry><literal>win1251_to_koi8r</literal></entry>
+ <entry><literal>WIN</literal></entry>
+ <entry><literal>KOI8</literal></entry>
</row>
<row>
- <entry>win1251_to_mic</entry>
- <entry>WIN</entry>
- <entry>MULE_INTERNAL</entry>
+ <entry><literal>win1251_to_mic</literal></entry>
+ <entry><literal>WIN</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
</row>
<row>
- <entry>win1251_to_utf_8</entry>
- <entry>WIN</entry>
- <entry>UNICODE</entry>
+ <entry><literal>win1251_to_utf_8</literal></entry>
+ <entry><literal>WIN</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>win1251_to_win866</entry>
- <entry>WIN</entry>
- <entry>ALT</entry>
+ <entry><literal>win1251_to_win866</literal></entry>
+ <entry><literal>WIN</literal></entry>
+ <entry><literal>ALT</literal></entry>
</row>
<row>
- <entry>win1256_to_utf_8</entry>
- <entry>WIN1256</entry>
- <entry>UNICODE</entry>
+ <entry><literal>win1256_to_utf_8</literal></entry>
+ <entry><literal>WIN1256</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>win866_to_iso_8859_5</entry>
- <entry>ALT</entry>
- <entry>ISO_8859_5</entry>
+ <entry><literal>win866_to_iso_8859_5</literal></entry>
+ <entry><literal>ALT</literal></entry>
+ <entry><literal>ISO_8859_5</literal></entry>
</row>
<row>
- <entry>win866_to_koi8r</entry>
- <entry>ALT</entry>
- <entry>KOI8</entry>
+ <entry><literal>win866_to_koi8r</literal></entry>
+ <entry><literal>ALT</literal></entry>
+ <entry><literal>KOI8</literal></entry>
</row>
<row>
- <entry>win866_to_mic</entry>
- <entry>ALT</entry>
- <entry>MULE_INTERNAL</entry>
+ <entry><literal>win866_to_mic</literal></entry>
+ <entry><literal>ALT</literal></entry>
+ <entry><literal>MULE_INTERNAL</literal></entry>
</row>
<row>
- <entry>win866_to_utf_8</entry>
- <entry>ALT</entry>
- <entry>UNICODE</entry>
+ <entry><literal>win866_to_utf_8</literal></entry>
+ <entry><literal>ALT</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
<row>
- <entry>win866_to_win1251</entry>
- <entry>ALT</entry>
- <entry>WIN</entry>
+ <entry><literal>win866_to_win1251</literal></entry>
+ <entry><literal>ALT</literal></entry>
+ <entry><literal>WIN</literal></entry>
</row>
<row>
- <entry>win874_to_utf_8</entry>
- <entry>WIN874</entry>
- <entry>UNICODE</entry>
+ <entry><literal>win874_to_utf_8</literal></entry>
+ <entry><literal>WIN874</literal></entry>
+ <entry><literal>UNICODE</literal></entry>
</row>
</tbody>
<!-- derived from the re_format.7 man page -->
<para>
- Regular expressions (<quote>RE</quote>s), as defined in
+ Regular expressions (<acronym>RE</acronym>s), as defined in
<acronym>POSIX</acronym>
- 1003.2, come in two forms: modern REs (roughly those of
+ 1003.2, come in two forms: modern <acronym>RE</acronym>s (roughly those of
<command>egrep</command>; 1003.2 calls these
- <quote>extended</quote> REs) and obsolete REs (roughly those of
- <command>ed</command>; 1003.2 <quote>basic</quote> REs).
+ <quote>extended</quote> <acronym>RE</acronym>s) and obsolete <acronym>RE</acronym>s (roughly those of
+ <command>ed</command>; 1003.2 <quote>basic</quote> <acronym>RE</acronym>s).
<productname>PostgreSQL</productname> implements the modern form.
</para>
</para>
<para>
- There is no particular limit on the length of REs, except insofar
+ There is no particular limit on the length of <acronym>RE</acronym>s, except insofar
as memory is limited. Memory usage is approximately linear in RE
size, and largely insensitive to RE complexity, except for bounded
repetitions. Bounded repetitions are implemented by macro
</para>
</tip>
- <bridgehead renderas="sect2">CASE</bridgehead>
+ <bridgehead renderas="sect2"><literal>CASE</></bridgehead>
<synopsis>
CASE WHEN <replaceable>condition</replaceable> THEN <replaceable>result</replaceable>
<replaceable>condition</replaceable> is true then the value of the
case expression is the <replaceable>result</replaceable> in the
<token>ELSE</token> clause. If the <token>ELSE</token> clause is
- omitted and no condition matches, the result is NULL.
+ omitted and no condition matches, the result is null.
</para>
<informalexample>
all the <replaceable>value</replaceable>s in the
<token>WHEN</token> clauses until one is found that is equal. If
no match is found, the <replaceable>result</replaceable> in the
- <token>ELSE</token> clause (or NULL) is returned. This is similar
+ <token>ELSE</token> clause (or a null value) is returned. This is similar
to the <function>switch</function> statement in C.
</para>
</para>
</informalexample>
- <bridgehead renderas="sect2">COALESCE</bridgehead>
+ <bridgehead renderas="sect2"><literal>COALESCE</></bridgehead>
<synopsis>
<function>COALESCE</function>(<replaceable>value</replaceable>
<para>
The <function>COALESCE</function> function returns the first of its
- arguments that is not NULL. This is often useful to substitute a
- default value for NULL values when data is retrieved for display,
+ arguments that is not null. This is often useful to substitute a
+ default value for null values when data is retrieved for display,
for example:
<programlisting>
SELECT COALESCE(description, short_description, '(none)') ...
</programlisting>
</para>
- <bridgehead renderas="sect2">NULLIF</bridgehead>
+ <bridgehead renderas="sect2"><literal>NULLIF</></bridgehead>
<indexterm>
<primary>nullif</primary>
</synopsis>
<para>
- The <function>NULLIF</function> function returns NULL if and only
+ The <function>NULLIF</function> function returns a null value if and only
if <replaceable>value1</replaceable> and
<replaceable>value2</replaceable> are equal. Otherwise it returns
<replaceable>value1</replaceable>. This can be used to perform the
<para>
<function>current_schema</function> returns the name of the schema that is
- at the front of the search path (or NULL if the search path is
+ at the front of the search path (or a null value if the search path is
empty). This is the schema that will be used for any tables or
other named objects that are created without specifying a target schema.
<function>current_schemas(boolean)</function> returns an array of the names of all
<primary>search path</primary>
<secondary>changing at runtime</secondary>
</indexterm>
- The search path may be altered by a runtime-alterable GUC setting. The
+ The search path may be altered by a run-time setting. The
command to use is <command>
SET SEARCH_PATH '<varname>schema</varname>'[,'<varname>schema</varname>']...
</command>
can access a function in a particular way. The possibilities for its
arguments are analogous to <function>has_table_privilege</function>.
When specifying a function by a text string rather than by OID,
- the allowed input is the same as for the <type>regprocedure</> datatype.
+ the allowed input is the same as for the <type>regprocedure</> data type.
The desired access type must currently evaluate to
<literal>EXECUTE</literal>.
</para>
visibility check for types, functions, operators, and operator classes,
respectively. For functions and operators, an object in the search path
is visible if there is no object of the same name <emphasis>and argument
- datatype(s)</> earlier in the path. For operator classes,
+ data type(s)</> earlier in the path. For operator classes,
both name and associated index access method are considered.
</para>
<para>
These functions extract comments previously stored with the
- <command>COMMENT</command> command. <literal>NULL</literal> is returned if
+ <command>COMMENT</command> command. A null value is returned if
no comment can be found matching the specified parameters.
</para>
<entry><function>count</function>(<replaceable class="parameter">expression</replaceable>)</entry>
<entry>
Counts the input values for which the value of <replaceable
- class="parameter">expression</replaceable> is not NULL.
+ class="parameter">expression</replaceable> is not null.
</entry>
<entry>The return value is of type <type>bigint</type>.</entry>
</row>
<para>
It should be noted that except for <function>COUNT</function>,
- these functions return NULL when no rows are selected. In
- particular, <function>SUM</function> of no rows returns NULL, not
+ these functions return a null value when no rows are selected. In
+ particular, <function>SUM</function> of no rows returns null, not
zero as one might expect. <function>COALESCE</function> may be
- used to substitute zero for NULL when necessary.
+ used to substitute zero for null when necessary.
</para>
</sect1>
</para>
<para>
- As usual, NULLs in the expressions or subquery rows are combined per
+ As usual, null values in the expressions or subquery rows are combined per
the normal rules of SQL Boolean expressions. Two rows are considered
equal if all their corresponding members are non-null and equal; the rows
are unequal if any corresponding members are non-null and unequal;
<tip>
<para>
<literal>x NOT IN y</literal> is equivalent to <literal>NOT (x IN y)</literal> in all
- cases. However, NULLs are much more likely to trip up the novice when
+ cases. However, null values are much more likely to trip up the novice when
working with <token>NOT IN</token> than when working with <token>IN</token>.
It's best to express your condition positively if possible.
</para>
</para>
<para>
- As usual, NULLs in the expressions or subquery rows are combined per
+ As usual, null values in the expressions or subquery rows are combined per
the normal rules of SQL Boolean expressions. Two rows are considered
equal if all their corresponding members are non-null and equal; the rows
are unequal if any corresponding members are non-null and unequal;
</para>
<para>
- As usual, NULLs in the expressions or subquery rows are combined per
+ As usual, null values in the expressions or subquery rows are combined per
the normal rules of SQL Boolean expressions. Two rows are considered
equal if all their corresponding members are non-null and equal; the rows
are unequal if any corresponding members are non-null and unequal;
</para>
<para>
- As usual, NULLs in the expressions or subquery rows are combined per
+ As usual, null values in the expressions or subquery rows are combined per
the normal rules of SQL Boolean expressions. Two rows are considered
equal if all their corresponding members are non-null and equal; the rows
are unequal if any corresponding members are non-null and unequal;
</para>
<para>
- As usual, NULLs in the expressions or subquery rows are combined per
+ As usual, null values in the expressions or subquery rows are combined per
the normal rules of SQL Boolean expressions. Two rows are considered
equal if all their corresponding members are non-null and equal; the rows
are unequal if any corresponding members are non-null and unequal;
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/indices.sgml,v 1.36 2002/08/13 20:40:43 momjian Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/indices.sgml,v 1.37 2002/09/21 18:32:53 petere Exp $ -->
<chapter id="indexes">
<title id="indexes-title">Indexes</title>
<note>
<para>
Testing has shown PostgreSQL's hash indexes to be similar or slower
- than btree indexes, and the index size and build time for hash
+ than B-tree indexes, and the index size and build time for hash
indexes is much worse. Hash indexes also suffer poor performance
under high concurrency. For these reasons, hash index use is
discouraged.
</listitem>
<listitem>
<para>
- Should not allow NULLs.
+ Should not allow null values.
</para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para>
- NULLs are acceptable.
+ Null values are acceptable.
</para>
</listitem>
</itemizedlist>
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/installation.sgml,v 1.81 2002/09/18 20:09:31 petere Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/installation.sgml,v 1.82 2002/09/21 18:32:53 petere Exp $ -->
<chapter id="installation">
<title><![%standalone-include[<productname>PostgreSQL</>]]>
*** You might have to rebuild your Perl installation. Refer to
*** the documentation for details.
</screen>
- (If you don't follow the onscreen output you will merely notice
+ (If you don't follow the on-screen output you will merely notice
the the PL/Perl library object will not be installed.) If you
see this, you will have to re-build and install
<productname>Perl</productname> manually to be able to build
<para>
To enable Native Language Support (<acronym>NLS</acronym>), that
is, the ability to display a program's messages in a language
- other than English, you need an implementation of the Gettext
+ other than English, you need an implementation of the <application>Gettext</>
<acronym>API</acronym>. Some operating systems have this
built-in (e.g., <systemitem class="osname">Linux</>, <systemitem
class="osname">NetBSD</>, <systemitem
<listitem>
<para>
- Kerberos, OpenSSL, or PAM, if you want to support
+ <application>Kerberos</>, <application>OpenSSL</>, or <application>PAM</>,
+ if you want to support
authentication using these services.
</para>
</listitem>
<term><option>--without-readline</option></term>
<listitem>
<para>
- Prevents the use of the Readline library. This disables
+ Prevents the use of the <application>Readline</> library. This disables
command-line editing and history in
<application>psql</application>, so it is not recommended.
</para>
<term><option>--without-zlib</option></term>
<listitem>
<para>
- Prevents the use of the Zlib library. This disables
+ Prevents the use of the <application>Zlib</> library. This disables
compression support in <application>pg_dump</application>.
This option is only intended for those rare systems where this
library is not available.
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/Attic/jdbc.sgml,v 1.37 2002/09/18 20:09:31 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/Attic/jdbc.sgml,v 1.38 2002/09/21 18:32:53 petere Exp $
-->
<chapter id="jdbc">
instructions. After installation, the driver should be found in
<filename><replaceable>PREFIX</>/share/java/postgresql.jar</filename>.
The resulting driver will be built for the version of Java you are
- running. If you build with a 1.1 JDK you will build a version
+ running. If you build with a 1.1 <acronym>JDK</> you will build a version
that supports the JDBC 1 specification, if you build with a Java 2
- JDK (e.g., JDK 1.2 or JDK 1.3) you will build a version that
+ <acronym>JDK</> (e.g., <acronym>JDK</> 1.2 or <acronym>JDK</> 1.3) you will build a version that
supports the JDBC 2 specification.
</para>
</sect2>
need to understand the limitations of each method. The
<type>bytea</type> data type is not well suited for storing very
large amounts of binary data. While a column of type
- <type>bytea</type> can hold upto 1Gig of binary data, it would
+ <type>bytea</type> can hold up to 1 GB of binary data, it would
require a huge amount of memory (<acronym>RAM</acronym>) to
process such a large value. The Large Object method for
storing binary data is better suited to storing very large values,
<formalpara>
<title>Throws:</title>
<para>
- SQLException by Fastpath when initializing for first time
+ <classname>SQLException</> by Fastpath when initializing for first time
</para>
</formalpara>
</listitem>
<para>
This adds a function to our look-up table. User code should
use the <function>addFunctions</function> method, which is based upon a query,
- rather than hard coding the oid. The oid for a function is not
+ rather than hard coding the OID. The OID for a function is not
guaranteed to remain static, even on different servers of the
same version.
</para>
</synopsis>
<para>
This takes a <classname>ResultSet</classname> containing two columns. Column 1
- contains the function name, Column 2 the oid. It reads the
+ contains the function name, Column 2 the OID. It reads the
entire <classname>ResultSet</classname>, loading the values into the function table.
</para>
<para>
<variablelist>
<varlistentry>
- <term>buf</term>
+ <term><parameter>buf</></term>
<listitem>
<simpara>destination array</simpara>
</listitem>
</varlistentry>
<varlistentry>
- <term>off</term>
+ <term><parameter>off</></term>
<listitem>
<simpara>offset within array</simpara>
</listitem>
</varlistentry>
<varlistentry>
- <term>len</term>
+ <term><parameter>len</></term>
<listitem>
<simpara>number of bytes to read</simpara>
</listitem>
<para>
<variablelist>
<varlistentry>
- <term>buf</term>
+ <term><parameter>buf</></term>
<listitem>
<simpara>destination array</simpara>
</listitem>
</varlistentry>
<varlistentry>
- <term>off</term>
+ <term><parameter>off</></term>
<listitem>
<simpara>offset within array</simpara>
</listitem>
</varlistentry>
<varlistentry>
- <term>len</term>
+ <term><parameter>len</></term>
<listitem>
<simpara>number of bytes to write</simpara>
</listitem>
<variablelist>
<varlistentry>
- <term>public static final int WRITE</term>
+ <term><literal>public static final int WRITE</></term>
<listitem>
<simpara>This mode indicates we want to write to an object.</simpara>
</listitem>
</varlistentry>
<varlistentry>
- <term>public static final int READ</term>
+ <term><literal>public static final int READ</></term>
<listitem>
<simpara>This mode indicates we want to read an object.</simpara>
</listitem>
</varlistentry>
<varlistentry>
- <term>public static final int READWRITE</term>
+ <term><literal>public static final int READWRITE</></term>
<listitem>
<simpara>This mode is the default. It indicates we want read and write access to a large object.</simpara>
</listitem>
</synopsis>
<para>
This opens an existing large object, based on its OID. This
- method assumes that READ and WRITE access is required (the
- default).
+ method assumes that <symbol>READ</> and
+ <symbol>WRITE</> access is required (the default).
</para>
</listitem>
</synopsis>
<para>
This creates a large object, returning its OID.
- It defaults to READWRITE for the new object's attributes.
+ It defaults to <symbol>READWRITE</> for the new object's attributes.
</para>
</listitem>
<LISTITEM>
<PARA>Specifies the name of an array variable where result tuples are stored,
indexed by the field names.
-This is ignored if queryString is not a SELECT statement. For SELECT
+This is ignored if <replaceable class=parameter>queryString</> is not a SELECT statement. For SELECT
statements, if this option is not used, result tuples values are stored
in individual variables named according to the field names in the result.
</PARA>
If the query is not a SELECT statement, the query is executed and the
number of tuples affected by the query is returned. If the query is an
INSERT and a single tuple is inserted, the OID of the inserted tuple is
-stored in the
oidVar variable if the optional <PARAMETER>-oid</PARAMETER>
+stored in the
<replaceable>oidVar</> variable if the optional <PARAMETER>-oid</PARAMETER>
argument is supplied.
</PARA>
<PARA>
has been omitted for clarity.
</PARA>
<PARA>
-Insert a row and save the OID in result_oid:
+Insert a row and save the OID in <varname>result_oid</>:
<ProgramListing>
pg_execute -oid result_oid $pgconn "insert into mytable values (1)"
</ProgramListing>
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-->
<chapter id="libpq">
environment variable (see <xref linkend="libpq-envars">)
is checked. If the environment variable is not set either,
then hardwired defaults are used.
- The return value is a pointer to an abstract struct
+ The return value is a pointer to an abstract <type>struct</type>
representing the connection to the backend.
</para>
</listitem>
Returns a connection options array. This may
be used to determine all possible <function>PQconnectdb</function> options and their
current default values. The return value points to an array of
- <structname>PQconninfoOption</structname> structs, which ends with an entry having a NULL
+ <structname>PQconninfoOption</structname> <type>struct</>s, which ends with an entry having a NULL
keyword pointer. Note that the default values (<structfield>val</structfield> fields)
will depend on environment variables and other context.
Callers must treat the connection options data as read-only.
at the contents of <structname>PGconn</structname>. Avoid directly referencing the fields of the
<structname>PGconn</> structure because they are subject to change in the future.
(Beginning in <productname>PostgreSQL</productname> release 6.4, the
-definition of struct <structname>PGconn</structname> is not even provided in <filename>libpq-fe.h</filename>.
+definition of <type>struct PGconn</> is not even provided in <filename>libpq-fe.h</filename>.
If you have old code that accesses <structname>PGconn</structname> fields directly, you can keep using it
by including <filename>libpq-int.h</filename> too, but you are encouraged to fix the code
soon.)
at the contents of <structname>PGresult</structname>. Avoid directly referencing the fields of the
<structname>PGresult</structname> structure because they are subject to change in the future.
(Beginning in <productname>PostgreSQL</productname> 6.4, the
-definition of struct <structname>PGresult</structname> is not even provided in <filename>libpq-fe.h</>. If you
+definition of <type>struct PGresult</> is not even provided in <filename>libpq-fe.h</>. If you
have old code that accesses <structname>PGresult</structname> fields directly, you can keep using it
by including <filename>libpq-int.h</filename> too, but you are encouraged to fix the code
soon.)
<listitem>
<para>
<function>PQresStatus</function>
- Converts the enumerated type returned by PQresultStatus into
+ Converts the enumerated type returned by <function>PQresultStatus</> into
a string constant describing the status code.
<synopsis>
char *PQresStatus(ExecStatusType status);
<structname>PGresult</structname> object. It is exported because some applications find it
useful to generate result objects (particularly objects with error
status) themselves. If <parameter>conn</parameter> is not NULL and status indicates an error,
-the connection's current errorMessage is copied into the <structname>PGresult.</structname>
+the connection's current error message is copied into the <structname>PGresult.</structname>
Note that <function>PQclear</function> should eventually be called on the object, just
as with a <structname>PGresult</structname> returned by <application>libpq</application> itself.
</para>
The <parameter>from</parameter> parameter points to an escaped string
such as might be returned by <function>PQgetvalue</function> of a
<type>BYTEA</type> column. <function>PQunescapeBytea</function> converts
- this NUL terminated string representation into binary, filling a buffer.
+ this string representation into its binary representation, filling the supplied buffer.
It returns a pointer to the buffer which is NULL on error, and the size
of the buffer in <parameter>to_length</parameter>. The pointer may
subsequently be used as an argument to the function
<listitem>
<para>
<function>PQbinaryTuples</function>
- Returns 1 if the PGresult contains binary tuple data,
+ Returns 1 if the <structname>PGresult</> contains binary tuple data,
0 if it contains ASCII data.
<synopsis>
int PQbinaryTuples(const PGresult *res);
indicating that the command is done. (If called when no command is
active, <function>PQgetResult</function> will just return NULL at once.)
Each non-NULL result from <function>PQgetResult</function> should be processed using
- the same PGresult accessor functions previously described.
+ the same <structname>PGresult</> accessor functions previously described.
Don't forget to free each result object with <function>PQclear</function> when done with it.
Note that <function>PQgetResult</function> will block only if a query is active and the
necessary response data has not yet been read by <function>PQconsumeInput</function>.
} u;
} PQArgBlock;
</synopsis>
- <function>PQfn</function> always returns a valid <structname>PGresult*</structname>. The resultStatus
+ <function>PQfn</function> always returns a valid <structname>PGresult*</structname>. The result status
should be checked before the result is used. The
caller is responsible for freeing the <structname>PGresult</structname> with
<function>PQclear</function> when it is no longer needed.
Returns the next notification from a list of unhandled
notification messages received from the backend. Returns NULL if
there are no pending notifications. Once a notification is
- returned from PQnotifies, it is considered handled and will be
+ returned from <function>PQnotifies</>, it is considered handled and will be
removed from the list of notifications.
<synopsis>
PGnotify* PQnotifies(PGconn *conn);
<para>
<function>PQsetNoticeProcessor</function>
<indexterm><primary>notice processor</></>
-Control reporting of notice and warning messages generated by libpq.
+Control reporting of notice and warning messages generated by <application>libpq</>.
<synopsis>
typedef void (*PQnoticeProcessor) (void *arg, const char *message);
<!--
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+$Header: /cvsroot/pgsql/doc/src/sgml/maintenance.sgml,v 1.19 2002/09/21 18:32:53 petere Exp $
-->
<chapter id="maintenance">
</indexterm>
<para>
- <productname>PostgreSQL</productname> is unable to reuse btree index
+ <productname>PostgreSQL</productname> is unable to reuse B-tree index
pages in certain cases. The problem is that if indexed rows are
deleted, those index pages can only be reused by rows with similar
values. For example, if indexed rows are deleted and newly
inserted/updated rows have much higher values, the new rows can't use
the index space made available by the deleted rows. Instead, such
new rows must be placed on new index pages. In such cases, disk
- space used by the index will grow indefinately, even if
+ space used by the index will grow indefinitely, even if
<command>VACUUM</> is run frequently.
</para>
<para>
The simplest production-grade approach to managing log output is to
send it all to <application>syslog</> and let
<application>syslog</> deal with file rotation. To do this, set
- <literal>syslog</> to 2 (log to syslog only) in
+ <literal>syslog</> to 2 (log to <application>syslog</> only) in
<filename>postgresql.conf</>. Then you can send a
<literal>SIGHUP</literal> signal to the <application>syslog</>
daemon whenever you want to force it to start writing a new log
</para>
<para>
- On many systems, however, syslog is not very reliable, particularly
+ On many systems, however, <application>syslog</> is not very reliable, particularly
with large log messages; it may truncate or drop messages just when
you need them the most. You may find it more useful to pipe the
<application>postmaster</>'s <systemitem>stderr</> to some type of
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-->
<chapter id="monitoring">
Each individual server process transmits new access counts to the collector
just before waiting for another client command; so a query still in
progress does not affect the displayed totals. Also, the collector itself
- emits new totals at most once per PGSTAT_STAT_INTERVAL (500 milliseconds
+ emits new totals at most once per <varname>pgstat_stat_interval</varname> (500 milliseconds
by default). So the displayed totals lag behind actual activity.
</para>
<tbody>
<row>
<entry><structname>pg_stat_activity</></entry>
- <entry>One row per server process, showing process PID, database,
+ <entry>One row per server process, showing process <acronym>PID</>, database,
user, and current query. The current query column is only available
to superusers; for others it reads as NULL. (Note that because of
the collector's reporting delay, current query will only be up-to-date
<row>
<entry><structname>pg_statio_sys_tables</></entry>
- <entry>Same as pg_statio_all_tables, except that only system tables
+ <entry>Same as <structname>pg_statio_all_tables</>, except that only system tables
are shown.</entry>
</row>
<row>
<entry><structname>pg_statio_user_tables</></entry>
- <entry>Same as pg_statio_all_tables, except that only user tables
+ <entry>Same as <structname>pg_statio_all_tables</>, except that only user tables
are shown.</entry>
</row>
<row>
<entry><structname>pg_statio_sys_indexes</></entry>
- <entry>Same as pg_statio_all_indexes, except that only indexes on
+ <entry>Same as <structname>pg_statio_all_indexes</>, except that only indexes on
system tables are shown.</entry>
</row>
<row>
<entry><structname>pg_statio_user_indexes</></entry>
- <entry>Same as pg_statio_all_indexes, except that only indexes on
+ <entry>Same as <structname>pg_statio_all_indexes</>, except that only indexes on
user tables are shown.</entry>
</row>
<row>
<entry><structname>pg_statio_sys_sequences</></entry>
- <entry>Same as pg_statio_all_sequences, except that only system
+ <entry>Same as <structname>pg_statio_all_sequences</>, except that only system
sequences are shown. (Presently, no system sequences are defined,
so this view is always empty.)</entry>
</row>
<row>
<entry><structname>pg_statio_user_sequences</></entry>
- <entry>Same as pg_statio_all_sequences, except that only user
+ <entry>Same as <structname>pg_statio_all_sequences</>, except that only user
sequences are shown.</entry>
</row>
</tbody>
<para>
The function <function>pg_stat_get_backend_idset</function> provides
a convenient way to generate one row for each active backend. For
- example, to show the PIDs and current queries of all backends:
+ example, to show the <acronym>PID</>s and current queries of all backends:
<programlisting>
SELECT pg_stat_get_backend_pid(S.backendid) AS procpid,
<entry><structfield>transaction</structfield></entry>
<entry><type>xid</type></entry>
<entry>The ID of a transaction, or NULL if the lockable object
- is a relation. Every transaction holds ExclusiveLock on its
+ is a relation. Every transaction holds an exclusive lock on its
transaction ID for its entire duration. If one transaction finds
it necessary to wait specifically for another transaction, it
- does so by attempting to acquire ShareLock on the other transaction
+ does so by attempting to acquire share lock on the other transaction
ID. That will succeed only when the other transaction terminates
and releases its locks.
</entry>
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-$Header: /cvsroot/pgsql/doc/src/sgml/mvcc.sgml,v 2.27 2002/08/17 13:04:14 momjian Exp $
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-->
<chapter id="mvcc">
EXCLUSIVE</literal>, <literal>EXCLUSIVE</literal>, and
<literal>ACCESS EXCLUSIVE</literal> lock modes.
This mode protects a table against
- concurrent schema changes and VACUUMs.
+ concurrent schema changes and <command>VACUUM</> runs.
</para>
<para>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/perform.sgml,v 1.20 2002/03/24 17:11:37 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/perform.sgml,v 1.21 2002/09/21 18:32:53 petere Exp $
-->
<chapter id="performance-tips">
</sect1>
<sect1 id="explicit-joins">
- <title>Controlling the Planner with Explicit JOINs</title>
+ <title>Controlling the Planner with Explicit <literal>JOIN</> Clauses</title>
<para>
Beginning with <productname>PostgreSQL</productname> 7.1 it is possible
- to control the query planner to some extent by using explicit JOIN
+ to control the query planner to some extent by using explicit <literal>JOIN</>
syntax. To see why this matters, we first need some background.
</para>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/plperl.sgml,v 2.17 2002/09/18 20:09:32 petere Exp $
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-->
<chapter id="plperl">
Access to the database itself from your Perl function can be done via
an experimental module <ulink
url="http://www.cpan.org/modules/by-module/DBD/APILOS/"><literal>DBD::PgSPI</literal></ulink>
- (also available at <ulink url="http://www.cpan.org/SITES.html">CPAN
+ (also available at <ulink url="http://www.cpan.org/SITES.html"><acronym>CPAN</>
mirror sites</ulink>). This module makes available a
<acronym>DBI</>-compliant database-handle named
<varname>$pg_dbh</varname> that can be used to perform queries
restricted --- for example, one might want a Perl function that
sends mail. To handle these cases, PL/Perl can also be installed
as an <quote>untrusted</> language (usually called
- <quote>PL/PerlU</quote>). In this case the full Perl language is
+ <application>PL/PerlU</application>). In this case the full Perl language is
available. If the <command>createlang</command> program is used to
install the language, the language name <literal>plperlu</literal>
will select the untrusted PL/Perl variant.
</para>
<para>
- The writer of a PL/PerlU function must take care that the function
+ The writer of a <application>PL/PerlU</> function must take care that the function
cannot be used to do anything unwanted, since it will be able to do
anything that could be done by a user logged in as the database
administrator. Note that the database system allows only database
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-->
<chapter id="plpgsql">
The <application>PL/pgSQL</application> EXECUTE statement is not
related to the EXECUTE statement supported by the
<productname>PostgreSQL</productname> backend. The backend
- EXECUTE statement cannot be used within PL/PgSQL functions (and
+ EXECUTE statement cannot be used within <application>PL/pgSQL</> functions (and
is not needed).
</para>
</note>
</para>
<para>
- If the SELECT query returns zero rows, NULLs are assigned to the
+ If the SELECT query returns zero rows, null values are assigned to the
target(s). If the SELECT query returns multiple rows, the first
row is assigned to the target(s) and the rest are discarded.
(Note that <quote>the first row</> is not well-defined unless you've
END IF;
</programlisting>
- Alternatively, you can use the IS NULL (or ISNULL) conditional to
- test for NULLity of a RECORD/ROW result. Note that there is no
+ Alternatively, you can use the <literal>IS NULL</literal> (or <literal>ISNULL</>) conditional to
+ test for whether a RECORD/ROW result is null. Note that there is no
way to tell whether any additional rows might have been discarded.
</para>
RETURN NEXT does not actually return from the function; it simply
saves away the value of the expression (or record or row variable,
- as appropriate for the datatype being returned).
+ as appropriate for the data type being returned).
Execution then continues with the next statement in the
<application>PL/pgSQL</> function. As successive RETURN NEXT
commands are executed, the result set is built up. A final
the function.
</para>
- <note>
- The current implementation of RETURN NEXT for PL/PgSQL stores
- the entire result set before returning from the function, as
- discussed above. That means that if a PL/PgSQL function
- produces a very large result set, performance may be poor: data
- will be written to disk to avoid memory exhaustion, but the
- function itself will not return until the entire
- result set has been generated. A future version of PL/PgSQL may
- allow users to allow users to define set-returning functions
- that do not have this limitation. Currently, the point at which
- data begins being written to disk is controlled by the
- <option>SORT_MEM</> configuration variable. Administrators who
- have sufficient memory to store larger result sets in memory
- should consider increasing this parameter.
- </para>
- </note>
- </sect2>
+ <note>
+ <para>
+ The current implementation of RETURN NEXT for
+ <application>PL/pgSQL</> stores the entire result set before
+ returning from the function, as discussed above. That means that
+ if a <application>PL/pgSQL</> function produces a very large result set,
+ performance may be poor: data will be written to disk to avoid
+ memory exhaustion, but the function itself will not return until
+ the entire result set has been generated. A future version of
+ <application>PL/pgSQL</> may allow users to allow users to define set-returning
+ functions that do not have this limitation. Currently, the point
+ at which data begins being written to disk is controlled by the
+ <varname>SORT_MEM</> configuration variable. Administrators who
+ have sufficient memory to store larger result sets in memory
+ should consider increasing this parameter.
+ </para>
+ </note>
+ </sect2>
<sect2 id="plpgsql-conditionals">
<title>Conditionals</title>
<para>
- <function>IF</function> statements let you execute commands based on
- certain conditions.
- <application>PL/pgSQL</> has four forms of IF: IF-THEN, IF-THEN-ELSE,
- IF-THEN-ELSE IF, and IF-THEN-ELSIF-THEN-ELSE.
+ <literal>IF</> statements let you execute commands based on
+ certain conditions. <application>PL/pgSQL</> has four forms of
+ <literal>IF</>:
+ <itemizedlist>
+ <listitem>
+ <para><literal>IF ... THEN</></>
+ </listitem>
+ <listitem>
+ <para><literal>IF ... THEN ... ELSE</></>
+ </listitem>
+ <listitem>
+ <para><literal>IF ... THEN ... ELSE IF</> and</>
+ </listitem>
+ <listitem>
+ <para><literal>IF ... THEN ... ELSIF ... THEN ... ELSE</></>
+ </listitem>
+ </itemizedlist>
</para>
<sect3>
- <title>IF-THEN</title>
+ <title><literal>IF-THEN</></title>
<para>
<synopsis>
</sect3>
<sect3>
- <title>IF-THEN-ELSE</title>
+ <title><literal>IF-THEN-ELSE</></title>
<para>
<synopsis>
</sect3>
<sect3>
- <title>IF-THEN-ELSE IF</title>
+ <title><literal>IF-THEN-ELSE IF</></title>
<para>
IF statements can be nested, as in the following example:
</sect3>
<sect3>
- <title>IF-THEN-ELSIF-ELSE</title>
+ <title><literal>IF-THEN-ELSIF-ELSE</></title>
<para>
<synopsis>
END IF;
</synopsis>
- IF-THEN-ELSIF-ELSE provides a more convenient method of checking
- many alternatives in one statement. Formally it is equivalent
- to nested IF-THEN-ELSE-IF-THEN commands, but only one END IF
- is needed.
+ <literal>IF-THEN-ELSIF-ELSE</> provides a more convenient
+ method of checking many alternatives in one statement.
+ Formally it is equivalent to nested
+ <literal>IF-THEN-ELSE-IF-THEN</> commands, but only one
+ <literal>END IF</> is needed.
</para>
<para>
to execute. The cursor cannot be open already, and it must
have been declared as an unbound cursor (that is, as a simple
<type>refcursor</> variable). The SELECT query is treated
- in the same way as other SELECTs in <application>PL/pgSQL</>:
+ in the same way as other SELECT
statements in <application>PL/pgSQL</>:
<application>PL/pgSQL</> variable names are substituted,
and the query plan is cached for possible re-use.
</sect3>
<sect3>
- <title>OPENing a bound cursor</title>
+ <title>Opening a bound cursor</title>
<para>
<synopsis>
caller. This is used to return multiple rows or columns from the
function. The function opens the cursor and returns the cursor
name to the caller. The caller can then FETCH rows from the
- cursor. The cursor can be CLOSEd by the caller, or it will be
+ cursor. The cursor can be closed by the caller, or it will be
closed automatically when the transaction closes.
</para>
Data type array of <type>text</type>; the arguments from
the <command>CREATE TRIGGER</command> statement.
The index counts from 0 and can be given as an expression. Invalid
- indices (< 0 or >= tg_nargs) result in a NULL value.
+ indices (< 0 or >= <varname>tg_nargs</>) result in a null value.
</para>
</listitem>
</varlistentry>
<row>
<entry>2</entry>
- <entry>In assignments, SELECTs, to delimit strings, etc.</entry>
+ <entry>In assignments, SELECT statements, to delimit strings, etc.</entry>
<entry><programlisting>
a_output := ''Blah'';
SELECT * FROM users WHERE f_name=''foobar'';
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/plpython.sgml,v 1.11 2002/09/18 20:09:32 petere Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/plpython.sgml,v 1.12 2002/09/21 18:32:53 petere Exp $ -->
<chapter id="plpython">
<title>PL/Python - Python Procedural Language</title>
execution environment, further restricts it to prevent the use of
the file <function>open</> call, and allows only modules from a
specific list to be imported. Presently, that list includes:
- array, bisect, binascii, calendar, cmath, codecs, errno, marshal,
- math, md5, mpz, operator, pcre, pickle, random, re, regex, sre,
- sha, string, StringIO, struct, time, whrandom, and zlib.
+ <literal>array</>, <>bisect</>, <>binascii</>, <>calendar</>,
+ <>cmath</>, <>codecs</>, <>errno</>, <>marshal</>, <>math</>,
+ <>md5</>, <>mpz</>, <>operator</>, <>pcre</>, <>pickle</>,
+ <>random</>, <>re</>, <>regex</>, <>sre</>, <>sha</>, <>string</>,
+ <>StringIO</>, <>struct</>, <>time</>, <>whrandom</>, and
+ <>zlib</>.
</para>
</sect1>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/pltcl.sgml,v 2.21 2002/08/22 00:01:40 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/pltcl.sgml,v 2.22 2002/09/21 18:32:53 petere Exp $
-->
<chapter id="pltcl">
<para>
Sometimes it is desirable to write Tcl functions that are not restricted
to safe Tcl --- for example, one might want a Tcl function that sends
- mail. To handle these cases, there is a variant of PL/Tcl called PL/TclU
+ mail. To handle these cases, there is a variant of <application>PL/Tcl</> called <literal>PL/TclU</>
(for untrusted Tcl). This is the exact same language except that a full
- Tcl interpreter is used. <emphasis>If PL/TclU is used, it must be
+ Tcl interpreter is used. <emphasis>If <application>PL/TclU</> is used, it must be
installed as an untrusted procedural language</emphasis> so that only
- database superusers can create functions in it. The writer of a PL/TclU
+ database superusers can create functions in it. The writer of a <application>PL/TclU</>
function must take care that the function cannot be used to do anything
unwanted, since it will be able to do anything that could be done by
a user logged in as the database administrator.
</para>
<para>
- The shared object for the PL/Tcl and PL/TclU call handlers is
+ The shared object for the <application>PL/Tcl</> and <application>PL/TclU</> call handlers is
automatically built and installed in the
<productname>PostgreSQL</productname>
library directory if Tcl/Tk support is specified
in the configuration step of the installation procedure. To install
- PL/Tcl and/or PL/TclU in a particular database, use the
+ <application>PL/Tcl</> and/or <application>PL/TclU</> in a particular database, use the
<filename>createlang</filename> script, for example
<literal>createlang pltcl <replaceable>dbname</></literal> or
<literal>createlang pltclu <replaceable>dbname</></literal>.
<title>PL/Tcl Functions and Arguments</title>
<para>
- To create a function in the PL/Tcl language, use the standard syntax
+ To create a function in the <application>PL/Tcl</> language, use the standard syntax
<programlisting>
CREATE FUNCTION <replaceable>funcname</replaceable> (<replaceable>argument-types</replaceable>) RETURNS <replaceable>return-type</replaceable> AS '
' LANGUAGE 'pltcl';
</programlisting>
- PL/TclU is the same, except that the language should be specified as
- <literal>'pltclu'</>.
+ <application>PL/TclU</> is the same, except that the language should be specified as
+ <literal>pltclu</>.
</para>
<para>
all PL/Tcl procedures executed in one backend share the same
safe Tcl interpreter. So, any global Tcl variable is accessible to
all PL/Tcl procedure calls, and will persist for the duration of the
- SQL client connection. (Note that PL/TclU functions likewise share
+ SQL client connection. (Note that <application>PL/TclU</> functions likewise share
global data, but they are in a different Tcl interpreter and cannot
communicate with PL/Tcl functions.)
</para>
setting up the query as a cursor and then saying <literal>FETCH n</>.
</para>
<para>
- If the query is a SELECT statement, the values of the SELECT's
+ If the query is a <literal>SELECT</> statement, the values of the statement's
result columns are placed into Tcl variables named after the columns.
If the <literal>-array</> option is given, the column values are
instead stored into the named associative array, with the SELECT
</programlisting>
will set the Tcl variable <literal>$cnt</> to the number of rows in
- the pg_proc system catalog.
+ the <structname>pg_proc</> system catalog.
</para>
<para>
If the optional <replaceable>loop-body</> argument is given, it is
<para>
The optional value for <literal>-nulls</> is a string of spaces and
<literal>'n'</> characters telling <function>spi_execp</function>
- which of the arguments are NULLs. If given, it must have exactly the
+ which of the arguments are null values. If given, it must have exactly the
same length as the <replaceable>value-list</replaceable>. If it
is not given, all the argument values are non-NULL.
</para>
<listitem>
<para>
A Tcl list of the table field names, prefixed with an empty list
- element. So looking up an element name in the list with Tcl's
+ element. So looking up an element name in the list with <application>Tcl</>'s
<function>lsearch</> command returns the element's number starting
with 1 for the first column, the same way the fields are customarily
numbered in <productname>PostgreSQL</productname>.
While the <literal>unknown</> module could actually contain any
initialization script you need, it normally defines a Tcl
<quote>unknown</> procedure that is invoked whenever Tcl does
- not recognize an invoked procedure name. PL/Tcl's standard version
+ not recognize an invoked procedure name. <application>PL/Tcl</>'s standard version
of this procedure tries to find a module in <literal>pltcl_modules</>
that will define the required procedure. If one is found, it is
loaded into the interpreter, and then execution is allowed to
differ. Tcl, however, requires all procedure names to be distinct.
PL/Tcl deals with this by making the internal Tcl procedure names contain
the object
- ID of the procedure's pg_proc row as part of their name. Thus,
+ ID of the procedure's <structname>pg_proc</> row as part of their name. Thus,
<productname>PostgreSQL</productname> functions with the same name
and different argument types will be different Tcl procedures too. This
is not normally a concern for a PL/Tcl programmer, but it might be visible
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/Attic/programmer.sgml,v 1.41 2002/09/18 20:07:15 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/Attic/programmer.sgml,v 1.42 2002/09/21 18:32:53 petere Exp $
PostgreSQL Programmer's Guide.
-->
&rules;
&xindex;
&indexcost;
- &gist;
&trigger;
&spi;
</part>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/alter_table.sgml,v 1.49 2002/08/15 02:59:18 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/alter_table.sgml,v 1.50 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
<para>
These forms change whether a column is marked to allow NULL
values or to reject NULL values. You may only <literal>SET NOT NULL</>
- when the table contains no NULLs in the column.
+ when the table contains no null values in the column.
</para>
</listitem>
</varlistentry>
compressible data. <literal>EXTERNAL</literal> is for external,
uncompressed data and <literal>EXTENDED</literal> is for external,
compressed data. <literal>EXTENDED</literal> is the default for all
- datatypes that support it. The use of <literal>EXTERNAL</literal> will
+ data types that support it. The use of <literal>EXTERNAL</literal> will
make substring operations on a TEXT column faster, at the penalty of
increased storage space.
</para>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/alter_user.sgml,v 1.22 2002/05/17 01:19:16 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/alter_user.sgml,v 1.23 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
<para>
Change a user's valid until date, specifying that his
authorization should expire at midday on 4th May 1998 using
- the time zone which is one hour ahead of UTC:
+ the time zone which is one hour ahead of <acronym>UTC</>:
<programlisting>
ALTER USER chris VALID UNTIL 'May 4 12:00:00 1998 +1';
</programlisting>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/begin.sgml,v 1.19 2002/08/30 22:45:25 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/begin.sgml,v 1.20 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
Guide</citetitle> for details.)
In SERIALIZABLE mode queries will see only changes committed before
the entire
- transaction began (actually, before execution of the first DML statement
+ transaction began (actually, before execution of the first <acronym>DML</> statement
in the transaction).
</para>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/cluster.sgml,v 1.19 2002/08/11 02:43:57 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/cluster.sgml,v 1.20 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
which uses the <productname>PostgreSQL</productname> sorting code in
the ORDER BY clause to create the desired order; this is usually much
- faster than an indexscan for
+ faster than an index scan for
unordered data. You then drop the old table, use
<command>ALTER TABLE...RENAME</command>
to rename <replaceable class="parameter">newtable</replaceable> to the old name, and
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/clusterdb.sgml,v 1.3 2002/09/05 22:05:50 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/clusterdb.sgml,v 1.4 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
<variablelist>
<varlistentry>
- <term>-d <replaceable class="parameter">dbname</replaceable></term>
- <term>--dbname <replaceable class="parameter">dbname</replaceable></term>
+ <term><option>-d <replaceable class="parameter">dbname</replaceable></></term>
+ <term><option>--dbname <replaceable class="parameter">dbname</replaceable></></term>
<listitem>
<para>
Specifies the name of the database to be clustered.
</varlistentry>
<varlistentry>
- <term>-a</term>
- <term>--all</term>
+ <term><option>-a</></term>
+ <term><option>--all</></term>
<listitem>
<para>
Cluster all databases.
</varlistentry>
<varlistentry>
- <term>-t <replaceable class="parameter">table</replaceable></term>
- <term>--table <replaceable class="parameter">table</replaceable></term>
+ <term><option>-t <replaceable class="parameter">table</replaceable></></term>
+ <term><option>--table <replaceable class="parameter">table</replaceable></></term>
<listitem>
<para>
Clusters <replaceable class="parameter">table</replaceable> only.
<variablelist>
<varlistentry>
- <term>-h <replaceable class="parameter">host</replaceable></term>
- <term>--host <replaceable class="parameter">host</replaceable></term>
+ <term><option>-h <replaceable class="parameter">host</replaceable></></term>
+ <term><option>--host <replaceable class="parameter">host</replaceable></></term>
<listitem>
<para>
Specifies the host name of the machine on which the
</varlistentry>
<varlistentry>
- <term>-p <replaceable class="parameter">port</replaceable></term>
- <term>--port <replaceable class="parameter">port</replaceable></term>
+ <term><option>-p <replaceable class="parameter">port</replaceable></></term>
+ <term><option>--port <replaceable class="parameter">port</replaceable></></term>
<listitem>
<para>
Specifies the Internet TCP/IP port or local Unix domain socket file
</varlistentry>
<varlistentry>
- <term>-U <replaceable class="parameter">username</replaceable></term>
- <term>--username <replaceable class="parameter">username</replaceable></term>
+ <term><option>-U <replaceable class="parameter">username</replaceable></></term>
+ <term><option>--username <replaceable class="parameter">username</replaceable></></term>
<listitem>
<para>
User name to connect as
</varlistentry>
<varlistentry>
- <term>-W</term>
- <term>--password</term>
+ <term><option>-W</></term>
+ <term><option>--password</></term>
<listitem>
<para>
Force password prompt.
</varlistentry>
<varlistentry>
- <term>-e</term>
- <term>--echo</term>
+ <term><option>-e</></term>
+ <term><option>--echo</></term>
<listitem>
<para>
Echo the commands that <application>clusterdb</application> generates
</varlistentry>
<varlistentry>
- <term>-q</term>
- <term>--quiet</term>
+ <term><option>-q</></term>
+ <term><option>--quiet</></term>
<listitem>
<para>
Do not display a response.
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/copy.sgml,v 1.39 2002/08/30 16:00:41 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/copy.sgml,v 1.40 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
<listitem>
<para>
int32 bit mask to denote important aspects of the file format. Bits are
-numbered from 0 (LSB) to 31 (MSB) --- note that this field is stored
+numbered from 0 (<acronym>LSB</>) to 31 (<acronym>MSB</>) --- note that this field is stored
with source's endianness, as are all subsequent integer fields. Bits
16-31 are reserved to denote critical file format issues; a reader
should abort if it finds an unexpected bit set in this range. Bits 0-15
Each tuple begins with an int16 count of the number of fields in the
tuple. (Presently, all tuples in a table will have the same count, but
that might not always be true.) Then, repeated for each field in the
-tuple, there is an int16 typlen word possibly followed by field data.
-The typlen field is interpreted thus:
+tuple, there is an int16 <structfield>typlen</> word possibly followed by field data.
+The <structfield>typlen</> field is interpreted thus:
<variablelist>
<varlistentry>
<listitem>
<para>
Field is a fixed-length data type. Exactly N
- bytes of data follow the typlen word.
+ bytes of data follow the <structfield>typlen</> word.
</para>
</listitem>
</varlistentry>
<term>-1</term>
<listitem>
<para>
- Field is a varlena data type. The next four
- bytes are the varlena header, which contains
+ Field is a <literal>varlena</> data type. The next four
+ bytes are the <literal>varlena</> header, which contains
the total value length including itself.
</para>
</listitem>
</para>
<para>
-For non-NULL fields, the reader can check that the typlen matches the
-expected typlen for the destination column. This provides a simple
+For non-NULL fields, the reader can check that the <structfield>typlen</> matches the
+expected <structfield>typlen</> for the destination column. This provides a simple
but very useful check that the data is as expected.
</para>
<para>
If OIDs are included in the dump, the OID field immediately follows the
field-count word. It is a normal field except that it's not included
-in the field-count. In particular it has a typlen --- this will allow
+in the field-count. In particular it has a <structfield>typlen</> --- this will allow
handling of 4-byte vs 8-byte OIDs without too much pain, and will allow
OIDs to be shown as NULL if that ever proves desirable.
</para>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_aggregate.sgml,v 1.20 2002/05/18 15:44:47 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_aggregate.sgml,v 1.21 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
If the state transition function is not strict, then it will be called
unconditionally at each input value, and must deal with NULL inputs
and NULL transition values for itself. This allows the aggregate
- author to have full control over the aggregate's handling of NULLs.
+ author to have full control over the aggregate's handling of null values.
</para>
<para>
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/create_conversion.sgml,v 1.3 2002/08/22 00:01:40 tgl Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/create_conversion.sgml,v 1.4 2002/09/21 18:32:54 petere Exp $ -->
<refentry id="SQL-CREATECONVERSION">
<refmeta>
<title>Examples</title>
<para>
- To create a conversion from encoding UNICODE to LATIN1 using myfunc:
+ To create a conversion from encoding UNICODE to LATIN1 using <function>myfunc</>:
<programlisting>
CREATE CONVERSION myconv FOR 'UNICODE' TO 'LATIN1' FROM myfunc;
</programlisting>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_database.sgml,v 1.28 2002/06/17 05:40:32 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_database.sgml,v 1.29 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
<term><computeroutput>ERROR: user '<replaceable class="parameter">username</replaceable>' is not allowed to create/drop databases</computeroutput></term>
<listitem>
<para>
- You must have the special CREATEDB privilege to create databases.
+ You must have the special <literal>CREATEDB</> privilege to create databases.
See <xref linkend="SQL-CREATEUSER" endterm="SQL-CREATEUSER-title">.
</para>
</listitem>
Normally, the creator becomes the owner of the new database.
Superusers can create databases owned by other users using the
<option>OWNER</> clause. They can even create databases owned by
- users with no special privileges. Non-superusers with CREATEDB
+ users with no special privileges. Non-superusers with <literal>CREATEDB</>
privilege can only create databases owned by themselves.
</para>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_function.sgml,v 1.42 2002/08/22 00:01:40 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_function.sgml,v 1.43 2002/09/21 18:32:54 petere Exp $
-->
<refentry id="SQL-CREATEFUNCTION">
Depending on the implementation language it may also be allowed
to specify <quote>pseudo-types</> such as <type>cstring</>.
Pseudo-types indicate that the actual argument type is either
- incompletely specified, or outside the set of ordinary SQL datatypes.
+ incompletely specified, or outside the set of ordinary SQL data types.
</para>
</listitem>
</varlistentry>
<literal>CALLED ON NULL INPUT</literal> (the default) indicates
that the function will be called normally when some of its
arguments are null. It is then the function author's
- responsibility to check for NULLs if necessary and respond
+ responsibility to check for null values if necessary and respond
appropriately.
</para>
<variablelist>
<varlistentry>
- <term>isStrict</term>
+ <term><literal>isStrict</></term>
<listitem>
<para>
Equivalent to <literal>STRICT</literal> or <literal>RETURNS NULL ON NULL INPUT</literal>
</varlistentry>
<varlistentry>
- <term>isCachable</term>
+ <term><literal>isCachable</></term>
<listitem>
<para>
<literal>isCachable</literal> is an obsolete equivalent of
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_index.sgml,v 1.36 2002/08/13 20:40:43 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_index.sgml,v 1.37 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
<para>
The expression used in the <command>WHERE</command> clause may refer
only to columns of the underlying table (but it can use all columns,
- not only the one(s) being indexed). Presently, sub-SELECTs and
+ not only the one(s) being indexed). Presently, subqueries and
aggregate expressions are also forbidden in <command>WHERE</command>.
</para>
</para>
<para>
Testing has shown PostgreSQL's hash indexes to be similar or slower
- than btree indexes, and the index size and build time for hash
+ than B-tree indexes, and the index size and build time for hash
indexes is much worse. Hash indexes also suffer poor performance
under high concurrency. For these reasons, hash index use is
discouraged.
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_opclass.sgml,v 1.2 2002/08/22 00:01:40 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_opclass.sgml,v 1.3 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
<listitem>
<para>
If present, the operator class will become the default index
- operator class for its datatype. At most one operator class
- can be the default for a specific datatype and access method.
+ operator class for its data type. At most one operator class
+ can be the default for a specific data type and access method.
</para>
</listitem>
</varlistentry>
<term><replaceable class="parameter">data_type</replaceable></term>
<listitem>
<para>
- The column datatype that this operator class is for.
+ The column data type that this operator class is for.
</para>
</listitem>
</varlistentry>
<term><replaceable class="parameter">type</replaceable></term>
<listitem>
<para>
- The input datatype(s) of an operator, or <literal>NONE</> to
- signify a left-unary or right-unary operator. The input datatypes
+ The input data type(s) of an operator, or <literal>NONE</> to
+ signify a left-unary or right-unary operator. The input data types
may be omitted in the normal case where they are the same as the
- operator class's datatype.
+ operator class's data type.
</para>
</listitem>
</varlistentry>
<term><replaceable class="parameter">parameter_types</replaceable></term>
<listitem>
<para>
- The parameter datatype(s) of the function.
+ The parameter data type(s) of the function.
</para>
</listitem>
</varlistentry>
<term><replaceable class="parameter">storage_type</replaceable></term>
<listitem>
<para>
- The datatype actually stored in the index. Normally this is the
- same as the column datatype, but some index access methods (only
+ The data type actually stored in the index. Normally this is the
+ same as the column data type, but some index access methods (only
GIST at this writing) allow it to be different. The
<literal>STORAGE</> clause must be omitted unless the index access
method allows a different type to be used.
<replaceable class="parameter">name</replaceable>.
</para>
<para>
- An operator class defines how a particular datatype can be used with
+ An operator class defines how a particular data type can be used with
an index. The operator class specifies that certain operators will fill
- particular roles or <quote>strategies</> for this datatype and this
+ particular roles or <quote>strategies</> for this data type and this
access method. The operator class also specifies the support procedures to
be used by
the index access method when the operator class is selected for an
</para>
<para>
The user who defines an operator class becomes its owner. The user
- must own the datatype for which the operator class is being defined,
+ must own the data type for which the operator class is being defined,
and must have execute permission for all referenced operators and functions.
</para>
</title>
<para>
The following example command defines a GiST index operator class
- for datatype <literal>_int4</> (array of int4). See
+ for data type <literal>_int4</> (array of int4). See
<filename>contrib/intarray/</> for the complete example.
</para>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_operator.sgml,v 1.31 2002/08/23 02:54:18 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_operator.sgml,v 1.32 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
are always equivalent.
</para>
<para>
- At least one of LEFTARG and RIGHTARG must be defined. For
+ At least one of <literal>LEFTARG</> and <literal>RIGHTARG</> must be defined. For
binary operators, both should be defined. For right unary
- operators, only LEFTARG should be defined, while for left
- unary operators only RIGHTARG should be defined.
+ operators, only <literal>LEFTARG</> should be defined, while for left
+ unary operators only <literal>RIGHTARG</> should be defined.
</para>
<para>
The
it also works to just have both operators refer to each other.)
</para>
<para>
- The HASHES, MERGES, SORT1, SORT2, LTCMP, and GTCMP options are present to
- support the query optimizer in performing joins.
- <productname>PostgreSQL</productname> can always evaluate a join (i.e.,
- processing a clause with two tuple variables separated by an operator that
- returns a <type>boolean</type>) by iterative substitution [WONG76]. In
- addition, <productname>PostgreSQL</productname> can use a hash-join
- algorithm along the lines of [SHAP86]; however, it must know whether this
- strategy is applicable. The current hash-join algorithm is only correct
- for operators that represent equality tests; furthermore, equality of the
- data type must mean bitwise equality of the representation of the type.
- (For example, a data type that contains unused bits that don't matter for
- equality tests could not be hash-joined.) The HASHES flag indicates to the
- query optimizer that a hash join may safely be used with this
- operator.
+ The <literal>HASHES</>, <literal>MERGES</>, <literal>SORT1</>,
+ <literal>SORT2</>, <literal>LTCMP</>, and <literal>GTCMP</> options
+ are present to support the query optimizer in performing joins.
+ <productname>PostgreSQL</productname> can always evaluate a join
+ (i.e., processing a clause with two tuple variables separated by an
+ operator that returns a <type>boolean</type>) by iterative
+ substitution <!--[WONG76]-->. In addition,
+ <productname>PostgreSQL</productname> can use a hash-join algorithm
+ <!--along the lines of [SHAP86]-->; however, it must know whether this
+ strategy is applicable. The current hash-join algorithm is only
+ correct for operators that represent equality tests; furthermore,
+ equality of the data type must mean bitwise equality of the
+ representation of the type. (For example, a data type that
+ contains unused bits that don't matter for equality tests could not
+ be hash-joined.) The <literal>HASHES</> flag indicates to the query optimizer
+ that a hash join may safely be used with this operator.
</para>
<para>
- Similarly, the MERGES flag indicates whether merge-sort is a usable join
- strategy for this operator. A merge join requires that the two input
- datatypes have consistent orderings, and that the mergejoin operator
- behave like equality with respect to that ordering. For example, it is
- possible to merge-join equality between an integer and a float variable by
- sorting both inputs in ordinary
- numeric order. Execution of a merge join requires that the system be
- able to identify four operators related to the mergejoin equality operator:
- less-than comparison for the left input datatype,
- less-than comparison for the right input datatype,
- less-than comparison between the two datatypes, and
- greater-than comparison between the two datatypes. It is possible to
- specify these by name, as the SORT1, SORT2, LTCMP, and GTCMP options
- respectively. The system will fill in the default names <literal><</>,
- <literal><</>, <literal><</>, <literal>></> respectively if
- any of these are omitted when MERGES is specified. Also, MERGES will
- be assumed to be implied if any of these four operator options appear.
+ Similarly, the <literal>MERGES</> flag indicates whether merge-sort
+ is a usable join strategy for this operator. A merge join requires
+ that the two input data types have consistent orderings, and that
+ the merge-join operator behave like equality with respect to that
+ ordering. For example, it is possible to merge-join equality
+ between an integer and a float variable by sorting both inputs in
+ ordinary numeric order. Execution of a merge join requires that
+ the system be able to identify four operators related to the
+ merge-join equality operator: less-than comparison for the left
+ input data type, less-than comparison for the right input data
+ type, less-than comparison between the two data types, and
+ greater-than comparison between the two data types. It is possible
+ to specify these by name, as the <literal>SORT1</>,
+ <literal>SORT2</>, <literal>LTCMP</>, and <literal>GTCMP</> options
+ respectively. The system will fill in the default names
+ <literal><</>, <literal><</>, <literal><</>,
+ <literal>></> respectively if any of these are omitted when
+ <literal>MERGES</> is specified. Also, <literal>MERGES</> will be
+ assumed to be implied if any of these four operator options appear.
</para>
<para>
If other join strategies are found to be practical,
be worth the complexity involved.
</para>
<para>
- The RESTRICT and JOIN options assist the query optimizer in estimating
- result sizes. If a clause of the form:
- <programlisting>
-MYBOXES.description <<< box '((0,0), (1,1))'
- </programlisting>
+ The <literal>RESTRICT</> and <literal>JOIN</> options assist the
+ query optimizer in estimating result sizes. If a clause of the
+ form:
+<programlisting>
+myboxes.description <<< box '((0,0), (1,1))'
+</programlisting>
is present in the qualification,
then <productname>PostgreSQL</productname> may have to
- estimate the fraction of the instances in MYBOXES that
+ estimate the fraction of the instances in <literal>myboxes</> that
satisfy the clause. The function
<replaceable class="parameter">res_proc</replaceable>
must be a registered function (meaning it is already defined using
<para>
Similarly, when the operands of the operator both contain
instance variables, the query optimizer must estimate the
- size of the resulting join. The function join_proc will
+ size of the resulting join. The function <function>join_proc</> will
return another floating-point number which will be multiplied
by the cardinalities of the two tables involved to
compute the expected result size.
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_schema.sgml,v 1.2 2002/05/18 15:44:47 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_schema.sgml,v 1.3 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
<term><replaceable class="parameter">schemaname</replaceable></term>
<listitem>
<para>
- The name of a schema to be created. If this is omitted, the username
+ The name of a schema to be created. If this is omitted, the user name
is used as the schema name.
</para>
</listitem>
<para>
A schema is essentially a namespace:
- it contains named objects (tables, datatypes, functions, and operators)
+ it contains named objects (tables, data types, functions, and operators)
whose names may duplicate those of other objects existing in other
schemas. Named objects are accessed either by <quote>qualifying</>
their names with the schema name as a prefix, or by setting a search
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_type.sgml,v 1.34 2002/08/29 00:17:01 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_type.sgml,v 1.35 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
specified schema. Otherwise it is created in the current schema (the one
at the front of the search path; see <literal>CURRENT_SCHEMA()</>).
The type name must be distinct from the name of any existing type or
- domain in the same schema. (Because tables have associated datatypes,
+ domain in the same schema. (Because tables have associated data types,
type names also must not conflict with table names in the same schema.)
</para>
<type>cstring</type>, <type>OID</type>, <type>int4</type>.
(The first argument is the input text as a C string, the second
argument is the element type in case this is an array type,
- and the third is the typmod of the destination column, if known.)
- It should return a value of the datatype itself.
+ and the third is the <literal>typmod</> of the destination column, if known.)
+ It should return a value of the data type itself.
The output function may be
- declared as taking one argument of the new datatype, or as taking
+ declared as taking one argument of the new data type, or as taking
two arguments of which the second is type <type>OID</type>.
(The second argument is again the array element type for array types.)
The output function should return type <type>cstring</type>.
can be declared to have results or inputs of the new type, when they have
to be created before the new type can be created. The answer is that the
input function must be created first, then the output function, then the
- datatype.
+ data type.
<productname>PostgreSQL</productname> will first see the name of the new
- datatype as the return type of the input function. It will create a
+ data type as the return type of the input function. It will create a
<quote>shell</> type, which is simply a placeholder entry in
<literal>pg_type</>, and link the input function definition to the shell
type. Similarly the output function will be linked to the (now already
positive integer, or variable length, indicated by setting
<replaceable class="parameter">internallength</replaceable>
to <option>VARIABLE</option>. (Internally, this is represented
- by setting typlen to -1.) The internal representation of all
+ by setting <literal>typlen</> to -1.) The internal representation of all
variable-length types must start with an integer giving the total
length of this value of the type.
</para>
<para>
The second form of <command>CREATE TYPE</command>
creates a composite type.
- The composite type is specified by a list of column names and datatypes.
+ The composite type is specified by a list of column names and data types.
This is essentially the same as the row type
of a table, but using <command>CREATE TYPE</command> avoids the need to
create an actual table when all that is wanted is to define a type.
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_view.sgml,v 1.19 2002/09/02 20:04:39 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_view.sgml,v 1.20 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
<listitem>
<para>
This option is to do with updatable views.
- All INSERTs and UPDATEs on the view will be
+ All <command>INSERT</> and <command>UPDATE</> commands on the view will be
checked to ensure data satisfy the view-defining
condition. If they do not, the update will be rejected.
</para>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/createdb.sgml,v 1.28 2002/08/10 16:57:31 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/createdb.sgml,v 1.29 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
<variablelist>
<varlistentry>
- <term>-h, --host <replaceable class="parameter">host</replaceable></term>
+ <term><option>-h <replaceable class="parameter">host</replaceable></></term>
+ <term><option>--host <replaceable class="parameter">host</replaceable></></term>
<listitem>
<para>
Specifies the host name of the machine on which the
</varlistentry>
<varlistentry>
- <term>-p, --port <replaceable class="parameter">port</replaceable></term>
+ <term><option>-p <replaceable class="parameter">port</replaceable></></term>
+ <term><option>--port <replaceable class="parameter">port</replaceable></></term>
<listitem>
<para>
Specifies the Internet TCP/IP port or the local Unix domain socket file
</varlistentry>
<varlistentry>
- <term>-U, --username <replaceable class="parameter">username</replaceable></term>
+ <term><option>-U <replaceable class="parameter">username</replaceable></></term>
+ <term><option>--username <replaceable class="parameter">username</replaceable></></term>
<listitem>
<para>
User name to connect as
</varlistentry>
<varlistentry>
- <term>-W, --password</term>
+ <term><option>-W</></term>
+ <term><option>--password</></term>
<listitem>
<para>
Force password prompt.
</varlistentry>
<varlistentry>
- <term>-e, --echo</term>
+ <term><option>-e</></term>
+ <term><option>--echo</></term>
<listitem>
<para>
Echo the queries that <application>createdb</application> generates
</varlistentry>
<varlistentry>
- <term>-q, --quiet</term>
+ <term><option>-q</></term>
+ <term><option>--quiet</></term>
<listitem>
<para>
Do not display a response.
</varlistentry>
<varlistentry>
- <term>-O, --owner <replaceable class="parameter">owner</replaceable></term>
+ <term><option>-O <replaceable class="parameter">owner</replaceable></></term>
+ <term><option>--owner <replaceable class="parameter">owner</replaceable></></term>
<listitem>
<para>
Specifies the database user who will own the new database.
</varlistentry>
<varlistentry>
- <term>-D, --location <replaceable class="parameter">datadir</replaceable></term>
+ <term><option>-D <replaceable class="parameter">datadir</replaceable></></term>
+ <term><option>--location <replaceable class="parameter">datadir</replaceable></></term>
<listitem>
<para>
Specifies the alternative location for the database. See also <xref
</varlistentry>
<varlistentry>
- <term>-T, --template <replaceable class="parameter">template</replaceable></term>
+ <term><option>-T <replaceable class="parameter">template</replaceable></></term>
+ <term><option>--template <replaceable class="parameter">template</replaceable></></term>
<listitem>
<para>
Specifies the template database from which to build this database.
</varlistentry>
<varlistentry>
- <term>-E, --encoding <replaceable class="parameter">encoding</replaceable></term>
+ <term><option>-E <replaceable class="parameter">encoding</replaceable></></term>
+ <term><option>--encoding <replaceable class="parameter">encoding</replaceable></></term>
<listitem>
<para>
Specifies the character encoding scheme to be used in this database.
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/createlang.sgml,v 1.26 2002/08/10 16:57:31 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/createlang.sgml,v 1.27 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
</varlistentry>
<varlistentry>
- <term>-d, --dbname <replaceable class="parameter">dbname</replaceable></term>
+ <term><option>-d <replaceable class="parameter">dbname</replaceable></></term>
+ <term><option>--dbname <replaceable class="parameter">dbname</replaceable></></term>
<listitem>
<para>
Specifies to which database the language should be added.
</varlistentry>
<varlistentry>
- <term>-e, --echo</term>
+ <term><option>-e</></term>
+ <term><option>--echo</></term>
<listitem>
<para>
Displays SQL commands as they are executed.
</varlistentry>
<varlistentry>
- <term>-l, --list</term>
+ <term><option>-l</></term>
+ <term><option>--list</></term>
<listitem>
<para>
Shows a list of already installed languages in the target database
</varlistentry>
<varlistentry>
- <term>--L <replaceable class="parameter">directory</replaceable></term>
+ <term><option>-L <replaceable class="parameter">directory</replaceable></></term>
<listitem>
<para>
Specifies the directory in which the language interpreter is
<variablelist>
<varlistentry>
- <term>-h, --host <replaceable class="parameter">host</replaceable></term>
+ <term><option>-h <replaceable class="parameter">host</replaceable></></term>
+ <term><option>--host <replaceable class="parameter">host</replaceable></></term>
<listitem>
<para>
Specifies the host name of the machine on which the
</varlistentry>
<varlistentry>
- <term>-p, --port <replaceable class="parameter">port</replaceable></term>
+ <term><option>-p <replaceable class="parameter">port</replaceable></></term>
+ <term><option>--port <replaceable class="parameter">port</replaceable></></term>
<listitem>
<para>
Specifies the Internet TCP/IP port or local Unix domain socket file
</varlistentry>
<varlistentry>
- <term>-U, --username <replaceable class="parameter">username</replaceable></term>
+ <term><option>-U <replaceable class="parameter">username</replaceable></></term>
+ <term><option>--username <replaceable class="parameter">username</replaceable></></term>
<listitem>
<para>
User name to connect as
</varlistentry>
<varlistentry>
- <term>-W, --password</term>
+ <term><option>-W</></term>
+ <term><option>--password</></term>
<listitem>
<para>
Force password prompt.
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/createuser.sgml,v 1.27 2002/08/10 16:57:31 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/createuser.sgml,v 1.28 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
<para>
Being a superuser also implies the ability to bypass access permission
- checks within the database, so superuser-dom should not be granted lightly.
+ checks within the database, so superuserdom should not be granted lightly.
</para>
<para>
<variablelist>
<varlistentry>
- <term>-h, --host <replaceable class="parameter">host</replaceable></term>
+ <term><option>-h <replaceable class="parameter">host</replaceable></></term>
+ <term><option>--host <replaceable class="parameter">host</replaceable></></term>
<listitem>
<para>
Specifies the host name of the machine on which the
</varlistentry>
<varlistentry>
- <term>-p, --port <replaceable class="parameter">port</replaceable></term>
+ <term><option>-p <replaceable class="parameter">port</replaceable></></term>
+ <term><option>--port <replaceable class="parameter">port</replaceable></></term>
<listitem>
<para>
Specifies the Internet TCP/IP port or local Unix domain socket file
</varlistentry>
<varlistentry>
- <term>-e, --echo</term>
+ <term><option>-e</></term>
+ <term><option>--echo</></term>
<listitem>
<para>
Echo the queries that <application>createuser</application> generates
</varlistentry>
<varlistentry>
- <term>-q, --quiet</term>
+ <term><option>-q</></term>
+ <term><option>--quiet</></term>
<listitem>
<para>
Do not display a response.
</varlistentry>
<varlistentry>
- <term>-d, --createdb</term>
+ <term><option>-d</></term>
+ <term><option>--createdb</></term>
<listitem>
<para>
The new user is allowed to create databases.
</varlistentry>
<varlistentry>
- <term>-D, --no-createdb</term>
+ <term><option>-D</></term>
+ <term><option>--no-createdb</></term>
<listitem>
<para>
The new user is not allowed to create databases.
</varlistentry>
<varlistentry>
- <term>-a, --adduser</term>
+ <term><option>-a</></term>
+ <term><option>--adduser</></term>
<listitem>
<para>
The new user is allowed to create other users.
</varlistentry>
<varlistentry>
- <term>-A, --no-adduser</term>
+ <term><option>-A</></term>
+ <term><option>--no-adduser</></term>
<listitem>
<para>
The new user is not allowed to create other users (i.e.,
</varlistentry>
<varlistentry>
- <term>-P, --pwprompt</term>
+ <term><option>-P</></term>
+ <term><option>--pwprompt</></term>
<listitem>
<para>
If given, <application>createuser</application> will issue a prompt for
</varlistentry>
<varlistentry>
- <term>-i, --sysid <replaceable class="parameter">uid</replaceable></term>
+ <term><option>-i <replaceable class="parameter">uid</replaceable></></term>
+ <term><option>--sysid <replaceable class="parameter">uid</replaceable></></term>
<listitem>
<para>
Allows you to pick a non-default user id for the new user. This is not
</varlistentry>
<varlistentry>
- <term>-E, --encrypted</term>
+ <term><option>-E</></term>
+ <term><option>--encrypted</></term>
<listitem>
<para>
Encrypts the user's password stored in the database. If not
</varlistentry>
<varlistentry>
- <term>-N, --unencrypted</term>
+ <term><option>-N</></term>
+ <term><option>--unencrypted</></term>
<listitem>
<para>
Does not encrypt the user's password stored in the database. If
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/drop_conversion.sgml,v 1.2 2002/07/22 13:00:00 ishii Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/drop_conversion.sgml,v 1.3 2002/09/21 18:32:54 petere Exp $ -->
<refentry id="SQL-DROPCONVERSION">
<refmeta>
<title>Examples</title>
<para>
- To drop the conversion named myname:
+ To drop the conversion named <literal>myname</>:
<programlisting>
DROP CONVERSION myname;
</programlisting>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/drop_opclass.sgml,v 1.1 2002/07/29 22:14:10 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/drop_opclass.sgml,v 1.2 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
Usage
</title>
<para>
- Remove btree operator class <literal>widget_ops</literal>:
+ Remove B-tree operator class <literal>widget_ops</literal>:
<programlisting>
DROP OPERATOR CLASS widget_ops USING btree;
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/dropdb.sgml,v 1.17 2002/08/10 16:57:31 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/dropdb.sgml,v 1.18 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
<variablelist>
<varlistentry>
- <term>-h, --host <replaceable class="parameter">host</replaceable></term>
+ <term><option>-h <replaceable class="parameter">host</replaceable></></term>
+ <term><option>--host <replaceable class="parameter">host</replaceable></></term>
<listitem>
<para>
Specifies the host name of the machine on which the
</varlistentry>
<varlistentry>
- <term>-p, --port <replaceable class="parameter">port</replaceable></term>
+ <term><option>-p <replaceable class="parameter">port</replaceable></></term>
+ <term><option>--port <replaceable class="parameter">port</replaceable></></term>
<listitem>
<para>
Specifies the Internet TCP/IP port or local Unix domain socket file
</varlistentry>
<varlistentry>
- <term>-U, --username <replaceable class="parameter">username</replaceable></term>
+ <term><option>-U <replaceable class="parameter">username</replaceable></></term>
+ <term><option>--username <replaceable class="parameter">username</replaceable></></term>
<listitem>
<para>
User name to connect as
</varlistentry>
<varlistentry>
- <term>-W, --password</term>
+ <term><option>-W</></term>
+ <term><option>--password</></term>
<listitem>
<para>
Force password prompt.
</varlistentry>
<varlistentry>
- <term>-e, --echo</term>
+ <term><option>-e</></term>
+ <term><option>--echo</></term>
<listitem>
<para>
Echo the queries that <application>dropdb</application> generates
</varlistentry>
<varlistentry>
- <term>-q, --quiet</term>
+ <term><option>-q</></term>
+ <term><option>--quiet</></term>
<listitem>
<para>
Do not display a response.
</varlistentry>
<varlistentry>
- <term>-i, --interactive</term>
+ <term><option>-i</></term>
+ <term><option>--interactive</></term>
<listitem>
<para>
Issues a verification prompt before doing anything destructive.
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/droplang.sgml,v 1.20 2002/08/10 16:57:31 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/droplang.sgml,v 1.21 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
</varlistentry>
<varlistentry>
- <term>[-d, --dbname] <replaceable class="parameter">dbname</replaceable></term>
+ <term><option><optional>-d</> <replaceable class="parameter">dbname</replaceable></></term>
+ <term><option><optional>--dbname</> <replaceable class="parameter">dbname</replaceable></></term>
<listitem>
<para>
Specifies from which database the language should be removed.
</varlistentry>
<varlistentry>
- <term>-e, --echo</term>
+ <term><option>-e</></term>
+ <term><option>--echo</></term>
<listitem>
<para>
Displays SQL commands as they are executed.
</varlistentry>
<varlistentry>
- <term>-l, --list</term>
+ <term><option>-l</></term>
+ <term><option>--list</></term>
<listitem>
<para>
Shows a list of already installed languages in the target database
<variablelist>
<varlistentry>
- <term>-h, --host <replaceable class="parameter">host</replaceable></term>
+ <term><option>-h <replaceable class="parameter">host</replaceable></></term>
+ <term><option>--host <replaceable class="parameter">host</replaceable></></term>
<listitem>
<para>
Specifies the host name of the machine on which the
</varlistentry>
<varlistentry>
- <term>-p, --port <replaceable class="parameter">port</replaceable></term>
+ <term><option>-p <replaceable class="parameter">port</replaceable></></term>
+ <term><option>--port <replaceable class="parameter">port</replaceable></></term>
<listitem>
<para>
Specifies the Internet TCP/IP port or local Unix domain socket file
</varlistentry>
<varlistentry>
- <term>-U, --username <replaceable class="parameter">username</replaceable></term>
+ <term><option>-U <replaceable class="parameter">username</replaceable></></term>
+ <term><option>--username <replaceable class="parameter">username</replaceable></></term>
<listitem>
<para>
User name to connect as
</varlistentry>
<varlistentry>
- <term>-W, --password</term>
+ <term><option>-W</></term>
+ <term><option>--password</></term>
<listitem>
<para>
Force password prompt.
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/dropuser.sgml,v 1.20 2002/08/10 16:57:31 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/dropuser.sgml,v 1.21 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
<variablelist>
<varlistentry>
- <term>-h, --host <replaceable class="parameter">host</replaceable></term>
+ <term><option>-h <replaceable class="parameter">host</replaceable></></term>
+ <term><option>--host <replaceable class="parameter">host</replaceable></></term>
<listitem>
<para>
Specifies the host name of the machine on which the
</varlistentry>
<varlistentry>
- <term>-p, --port <replaceable class="parameter">port</replaceable></term>
+ <term><option>-p <replaceable class="parameter">port</replaceable></></term>
+ <term><option>--port <replaceable class="parameter">port</replaceable></></term>
<listitem>
<para>
Specifies the Internet TCP/IP port or local Unix domain socket file
</varlistentry>
<varlistentry>
- <term>-e, --echo</term>
+ <term><option>-e</></term>
+ <term><option>--echo</></term>
<listitem>
<para>
Echo the queries that <application>dropuser</application> generates
</varlistentry>
<varlistentry>
- <term>-q, --quiet</term>
+ <term><option>-q</></term>
+ <term><option>--quiet</></term>
<listitem>
<para>
Do not display a response.
</varlistentry>
<varlistentry>
- <term>-i, --interactive</term>
+ <term><option>-i</></term>
+ <term><option>--interactive</></term>
<listitem>
<para>
Prompt for confirmation before actually removing the user.
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-->
<para>
<variablelist>
<varlistentry>
- <term>--pgdata=<replaceable class="parameter">directory</replaceable></term>
- <term>-D <replaceable class="parameter">directory</replaceable></term>
+ <term><option>--pgdata=<replaceable class="parameter">directory</replaceable></option></term>
+ <term><option>-D <replaceable class="parameter">directory</replaceable></option></term>
<listitem>
<para>
This option specifies the directory where the database system
</varlistentry>
<varlistentry>
- <term>--username=<replaceable class="parameter">username</replaceable></term>
- <term>-U <replaceable class="parameter">username</replaceable></term>
+ <term><option>--username=<replaceable class="parameter">username</replaceable></option></term>
+ <term><option>-U <replaceable class="parameter">username</replaceable></option></term>
<listitem>
<para>
Selects the user name of the database superuser. This defaults
to the name of the effective user running
<command>initdb</command>. It is really not important what the
superuser's name is, but one might choose to keep the
- customary name <quote>postgres</quote>, even if the operating
+ customary name <systemitem>postgres</systemitem>, even if the operating
system user's name is different.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>--pwprompt</term>
- <term>-W</term>
+ <term><option>--pwprompt</option></term>
+ <term><option>-W</option></term>
<listitem>
<para>
Makes <command>initdb</command> prompt for a password
</varlistentry>
<varlistentry>
- <term>--encoding=<replaceable class="parameter">encoding</replaceable></term>
- <term>-E <replaceable class="parameter">encoding</replaceable></term>
+ <term><option>--encoding=<replaceable class="parameter">encoding</replaceable></option></term>
+ <term><option>-E <replaceable class="parameter">encoding</replaceable></option></term>
<listitem>
<para>
Selects the encoding of the template database. This will also
</varlistentry>
<varlistentry>
- <term>--locale=<replaceable>locale</replaceable></term>
+ <term><option>--locale=<replaceable>locale</replaceable></option></term>
<listitem>
<para>
Sets the default locale for the database cluster. If this
</varlistentry>
<varlistentry>
- <term>--lc-collate=<replaceable>locale</replaceable></term>
- <term>--lc-ctype=<replaceable>locale</replaceable></term>
- <term>--lc-messages=<replaceable>locale</replaceable></term>
- <term>--lc-monetary=<replaceable>locale</replaceable></term>
- <term>--lc-numeric=<replaceable>locale</replaceable></term>
- <term>--lc-time=<replaceable>locale</replaceable></term>
+ <term><option>--lc-collate=<replaceable>locale</replaceable></option></term>
+ <term><option>--lc-ctype=<replaceable>locale</replaceable></option></term>
+ <term><option>--lc-messages=<replaceable>locale</replaceable></option></term>
+ <term><option>--lc-monetary=<replaceable>locale</replaceable></option></term>
+ <term><option>--lc-numeric=<replaceable>locale</replaceable></option></term>
+ <term><option>--lc-time=<replaceable>locale</replaceable></option></term>
<listitem>
<para>
<variablelist>
<varlistentry>
- <term>-L <replaceable class="parameter">directory</replaceable></term>
+ <term><option>-L <replaceable class="parameter">directory</replaceable></option></term>
<listitem>
<para>
Specifies where <command>initdb</command> should find
</varlistentry>
<varlistentry>
- <term>--noclean</term>
- <term>-n</term>
+ <term><option>-n</option></term>
+ <term><option>--noclean</option></term>
<listitem>
<para>
By default, when <command>initdb</command>
</varlistentry>
<varlistentry>
- <term>--debug</term>
- <term>-d</term>
+ <term><option>-d</option></term>
+ <term><option>--debug</option></term>
<listitem>
<para>
Print debugging output from the bootstrap backend and a few other
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PostgreSQL documentation
-->
<term>DEFAULT VALUES</term>
<listitem>
<para>
- All columns will be filled by NULLs or by values specified
- when the table was created using DEFAULT clauses.
+ All columns will be filled by null values or by values specified
+ when the table was created using <literal>DEFAULT</> clauses.
</para>
</listitem>
</varlistentry>
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PostgreSQL documentation
-->
<para>
The method a frontend application must use to detect notify events depends on
which <productname>PostgreSQL</productname> application programming interface it
- uses. With the basic libpq library, the application issues
+ uses. With the <application>libpq</> library, the application issues
<command>LISTEN</command> as an ordinary SQL command, and then must
periodically call the routine <function>PQnotifies</function> to find out
whether any notify events have been received. Other interfaces such as
- libpgtcl provide higher-level methods for handling notify events; indeed,
- with libpgtcl the application programmer should not even issue
+ <application>libpgtcl</> provide higher-level methods for handling notify events; indeed,
+ with <application>libpgtcl</> the application programmer should not even issue
<command>LISTEN</command> or <command>UNLISTEN</command> directly. See the
documentation for the library you are using for more details.
</para>
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-->
Conflicts with SHARE UPDATE EXCLUSIVE, SHARE, SHARE ROW EXCLUSIVE,
EXCLUSIVE and
ACCESS EXCLUSIVE modes. This mode protects a table against
- concurrent schema changes and VACUUMs.
+ concurrent schema changes and <command>VACUUM</> runs.
</para>
<note>
To achieve a similar effect when running a transaction
at the SERIALIZABLE isolation level, you have to execute the
<command>LOCK TABLE</>
- statement before executing any DML statement. A serializable
- transaction's view of data will be frozen when its first DML statement
+ statement before executing any <acronym>DML</> statement. A serializable
+ transaction's view of data will be frozen when its first <acronym>DML</> statement
begins. A later <command>LOCK</> will still prevent concurrent writes
--- but it
won't ensure that what the transaction reads corresponds to the latest
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PostgreSQL documentation
-->
</para>
<para>
The information passed to the frontend for a notify event includes the notify
- condition name and the notifying backend process's PID. It is up to the
+ condition name and the notifying backend process's <acronym>PID</>. It is up to the
database designer to define the condition names that will be used in a given
database and what each one means.
</para>
</para>
<para>
<command>NOTIFY</command> provides a simple form of signal or
- IPC (interprocess communication) mechanism for a collection of processes
+ <acronym>IPC</> (interprocess communication) mechanism for a collection of processes
accessing the same <productname>PostgreSQL</productname> database.
Higher-level mechanisms can be built by using tables in the database to
pass additional data (beyond a mere condition name) from notifier to
re-reading a database table to find the same updates that that frontend just
wrote out. In <productname>PostgreSQL</productname> 6.4 and later, it is
possible to avoid such extra work by noticing whether the notifying backend
- process's PID (supplied in the notify event message) is the same as one's own
- backend's PID (available from libpq). When they are the same, the notify
+ process's <acronym>PID</> (supplied in the notify event message) is the same as one's own
+ backend's <acronym>PID</> (available from <application>libpq</>). When they are the same, the notify
event is one's own work bouncing back, and can be ignored. (Despite what was
said in the preceding paragraph, this is a safe technique.
<productname>PostgreSQL</productname> keeps self-notifies separate from notifies
</para>
<para>
In <productname>PostgreSQL</productname> releases prior to 6.4, the backend
- PID delivered in a notify message was always the PID of the frontend's own
+ <acronym>PID</> delivered in a notify message was always the <acronym>PID</> of the frontend's own
backend. So it was not possible to distinguish one's own notifies from other
clients' notifies in those earlier releases.
</para>
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PostgreSQL documentation
-->
<para>
Append the server log output to
<replaceable>filename</replaceable>. If the file does not
- exist, it is created. The umask is set to 077, so access to
+ exist, it is created. The <systemitem>umask</> is set to 077, so access to
the log file from other users is disallowed by default.
</para>
</listitem>
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-->
Disables <function>fsync</function> calls for performance
improvement, at the risk of data corruption in event of a
system crash. This parameter corresponds to setting
- fsync=false in postgresql.conf. Read the detailed
+ <literal>fsync=false</> in <filename>postgresql.conf</>. Read the detailed
documentation before using this!
</para>
<para>
Allows clients to connect via TCP/IP (Internet domain)
connections. Without this option, only local Unix domain
socket connections are accepted. This option corresponds
- to setting tcpip_socket=true in postgresql.conf.
+ to setting <literal>tcpip_socket=true</> in <filename>postgresql.conf</>.
</para>
<para>
<option>--tcpip_socket=false</option> has the opposite
<listitem>
<para>
Default character encoding used by clients. (The clients may
- override this invidiually.) This value can also be set in the
+ override this individually.) This value can also be set in the
configuration file.
</para>
</listitem>
<listitem>
<para>
- Default port (preferrably set in the configuration file)
+ Default port (preferably set in the configuration file)
</para>
</listitem>
</varlistentry>
</para>
<para>
- The <option>--</> options will not work on FreeBSD or OpenBSD.
+ The <option>--</> options will not work on <systemitem
+ class="osname">FreeBSD</> or <systemitem class="osname">OpenBSD</>.
Use <option>-c</> instead. This is a bug in the affected operating
- systems; a future release of <productname>PostgreSQL</productname> will
- provide a workaround if this is not fixed.
+ systems; a future release of <productname>PostgreSQL</productname>
+ will provide a workaround if this is not fixed.
</para>
</refsect1>
</screen>
This command will start up <application>postmaster</application>
communicating through the port 1234. In order to connect to this
- <application>postmaster</application> using psql, you would need to
+ <application>postmaster</application> using <application>psql</>, you would need to
run it as
<screen>
<prompt>$</prompt> <userinput>psql -p 1234</userinput>
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PostgreSQL documentation
-->
<variablelist>
<varlistentry>
- <term>-a, --echo-all</term>
+ <term><option>-a</></term>
+ <term><option>--echo-all</></term>
<listitem>
<para>
Print all the lines to the screen as they are read. This is more
useful for script processing rather than interactive mode. This is
- equivalent to setting the variable <envar>ECHO</envar> to
+ equivalent to setting the variable <varname>ECHO</varname> to
<literal>all</literal>.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>-A, --no-align</term>
+ <term><option>-A</></term>
+ <term><option>--no-align</></term>
<listitem>
<para>
Switches to unaligned output mode. (The default output mode is
</varlistentry>
<varlistentry>
- <term>-c, --command <replaceable class="parameter">query</replaceable></term>
+ <term><option>-c <replaceable class="parameter">query</replaceable></></term>
+ <term><option>--command <replaceable class="parameter">query</replaceable></></term>
<listitem>
<para>
Specifies that <application>psql</application> is to execute one
</para>
<para>
<replaceable class="parameter">query</replaceable> must be either
- a query string that is completely parseable by the backend (i.e.,
+ a query string that is completely parsable by the backend (i.e.,
it contains no <application>psql</application> specific features),
or it is a single backslash command. Thus you cannot mix
<acronym>SQL</acronym> and <application>psql</application>
</varlistentry>
<varlistentry>
- <term>-d, --dbname <replaceable class="parameter">dbname</replaceable></term>
+ <term><option>-d <replaceable class="parameter">dbname</replaceable></></term>
+ <term><option>--dbname <replaceable class="parameter">dbname</replaceable></></term>
<listitem>
<para>
Specifies the name of the database to connect to. This is
</varlistentry>
<varlistentry>
- <term>-e, --echo-queries</term>
+ <term><option>-e</></term>
+ <term><option>--echo-queries</></term>
<listitem>
<para>
Show all queries that are sent to the backend. This is equivalent
- to setting the variable <envar>ECHO</envar> to
+ to setting the variable <varname>ECHO</varname> to
<literal>queries</literal>.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>-E, --echo-hidden</term>
+ <term><option>-E</></term>
+ <term><option>--echo-hidden</></term>
<listitem>
<para>
Echoes the actual queries generated by \d and other backslash
commands. You can use this if you wish to include similar
functionality into your own programs. This is equivalent to
- setting the variable <envar>ECHO_HIDDEN</envar> from within
+ setting the variable <varname>ECHO_HIDDEN</varname> from within
<application>psql</application>.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>-f, --file <replaceable class="parameter">filename</replaceable></term>
+ <term><option>-f <replaceable class="parameter">filename</replaceable></></term>
+ <term><option>--file <replaceable class="parameter">filename</replaceable></></term>
<listitem>
<para>
Use the file <replaceable class="parameter">filename</replaceable>
</varlistentry>
<varlistentry>
- <term>-F, --field-separator <replaceable class="parameter">separator</replaceable></term>
+ <term><option>-F <replaceable class="parameter">separator</replaceable></></term>
+ <term><option>--field-separator <replaceable class="parameter">separator</replaceable></></term>
<listitem>
<para>
Use <replaceable class="parameter">separator</replaceable> as the
</varlistentry>
<varlistentry>
- <term>-h, --host <replaceable class="parameter">hostname</replaceable></term>
+ <term><option>-h <replaceable class="parameter">hostname</replaceable></></term>
+ <term><option>--host <replaceable class="parameter">hostname</replaceable></></term>
<listitem>
<para>
Specifies the host name of the machine on which the
<application>postmaster</application> is running. If host begins
- with a slash, it is used as the directory for the unix domain
+ with a slash, it is used as the directory for the Unix-domain
socket.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>-H, --html</term>
+ <term><option>-H</></term>
+ <term><option>--html</></term>
<listitem>
<para>
Turns on <acronym>HTML</acronym> tabular output. This is
</varlistentry>
<varlistentry>
- <term>-l, --list</term>
+ <term><option>-l</></term>
+ <term><option>--list</></term>
<listitem>
<para>
Lists all available databases, then exits. Other non-connection
</varlistentry>
<varlistentry>
- <term>-o, --output <replaceable class="parameter">filename</replaceable></term>
+ <term><option>-o <replaceable class="parameter">filename</replaceable></></term>
+ <term><option>--output <replaceable class="parameter">filename</replaceable></></term>
<listitem>
<para>
Put all query output into file <replaceable
</varlistentry>
<varlistentry>
- <term>-p, --port <replaceable class="parameter">port</replaceable></term>
+ <term><option>-p <replaceable class="parameter">port</replaceable></></term>
+ <term><option>--port <replaceable class="parameter">port</replaceable></></term>
<listitem>
<para>
Specifies the TCP/IP port or, by omission, the local Unix domain
</varlistentry>
<varlistentry>
- <term>-P, --pset <replaceable class="parameter">assignment</replaceable></term>
+ <term><option>-P <replaceable class="parameter">assignment</replaceable></></term>
+ <term><option>--pset <replaceable class="parameter">assignment</replaceable></></term>
<listitem>
<para>
Allows you to specify printing options in the style of
</varlistentry>
<varlistentry>
- <term>-q</term>
+ <term><option>-q</></term>
+ <term><option>--quiet</></term>
<listitem>
<para>
Specifies that <application>psql</application> should do its work
informational output. If this option is used, none of this
happens. This is useful with the <option>-c</option> option.
Within <application>psql</application> you can also set the
- <envar>QUIET</envar> variable to achieve the same effect.
+ <varname>QUIET</varname> variable to achieve the same effect.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>-R, --record-separator <replaceable class="parameter">separator</replaceable></term>
+ <term><option>-R <replaceable class="parameter">separator</replaceable></></term>
+ <term><option>--record-separator <replaceable class="parameter">separator</replaceable></></term>
<listitem>
<para>
Use <replaceable class="parameter">separator</replaceable> as the
</varlistentry>
<varlistentry>
- <term>-s, --single-step</term>
+ <term><option>-s</></term>
+ <term><option>--single-step</></term>
<listitem>
<para>
Run in single-step mode. That means the user is prompted before
</varlistentry>
<varlistentry>
- <term>-S, --single-line</term>
+ <term><option>-S</></term>
+ <term><option>--single-line</></term>
<listitem>
<para>
Runs in single-line mode where a newline terminates a query, as a
</varlistentry>
<varlistentry>
- <term>-t, --tuples-only</term>
+ <term><option>-t</></term>
+ <term><option>--tuples-only</></term>
<listitem>
<para>
Turn off printing of column names and result row count footers,
</varlistentry>
<varlistentry>
- <term>-T, --table-attr <replaceable class="parameter">table_options</replaceable></term>
+ <term><option>-T <replaceable class="parameter">table_options</replaceable></></term>
+ <term><option>--table-attr <replaceable class="parameter">table_options</replaceable></></term>
<listitem>
<para>
Allows you to specify options to be placed within the
</varlistentry>
<varlistentry>
- <term>-u</term>
+ <term><option>-u</></term>
<listitem>
<para>
Makes <application>psql</application> prompt for the user name and
</varlistentry>
<varlistentry>
- <term>-U, --username <replaceable class="parameter">username</replaceable></term>
+ <term><option>-U <replaceable class="parameter">username</replaceable></></term>
+ <term><option>--username <replaceable class="parameter">username</replaceable></></term>
<listitem>
<para>
Connects to the database as the user <replaceable
</varlistentry>
<varlistentry>
- <term>-v, --variable, --set <replaceable class="parameter">assignment</replaceable></term>
+ <term><option>-v <replaceable class="parameter">assignment</replaceable></></term>
+ <term><option>--set <replaceable class="parameter">assignment</replaceable></></term>
+ <term><option>--variable <replaceable class="parameter">assignment</replaceable></></term>
<listitem>
<para>
Performs a variable assignment, like the <command>\set</command>
</varlistentry>
<varlistentry>
- <term>-V, --version</term>
+ <term><option>-V</></term>
+ <term><option>--version</></term>
<listitem>
<para>
Shows the <application>psql</application> version.
</varlistentry>
<varlistentry>
- <term>-W, --password</term>
+ <term><option>-W</></term>
+ <term><option>--password</></term>
<listitem>
<para>
Requests that <application>psql</application> should prompt for a
</varlistentry>
<varlistentry>
- <term>-x, --expanded</term>
+ <term><option>-x</></term>
+ <term><option>--expanded</></term>
<listitem>
<para>
Turns on extended row format mode. This is equivalent to the
</varlistentry>
<varlistentry>
- <term>-X, --no-psqlrc</term>
+ <term><option>-X,</></term>
+ <term><option>--no-psqlrc</></term>
<listitem>
<para>
Do not read the start-up file <filename>~/.psqlrc</filename>.
</varlistentry>
<varlistentry>
- <term>-?, --help</term>
+ <term><option>-?</></term>
+ <term><option>--help</></term>
<listitem>
<para>
Shows help about <application>psql</application> command line
finished normally, 1 if a fatal error of its own (out of memory,
file not found) occurs, 2 if the connection to the backend went bad
and the session is not interactive, and 3 if an error occurred in a
- script and the variable <envar>ON_ERROR_STOP</envar> was set.
+ script and the variable <varname>ON_ERROR_STOP</varname> was set.
</para>
</refsect1>
not belong to any option it will be interpreted as the database name
(or the user name, if the database name is also given). Not all
these options are required, defaults do apply. If you omit the host
- name psql will connect via a Unix domain socket to a server on the
+ name, <application>psql</> will connect via a Unix domain socket to a server on the
local host. The default port number is compile-time determined.
Since the database server uses the same default, you will not have
to specify the port in most cases. The default user name is your
</para>
<para>
- Arguments that are quoted in <quote>backticks</quote>
- (<literal>`</literal>) are taken as a command line that is passed to
- the shell. The output of the command (with any trailing newline
- removed) is taken as the argument value. The above escape sequences
- also apply in backticks.
+ Arguments that are enclosed in backquotes (<literal>`</literal>)
+ are taken as a command line that is passed to the shell. The
+ output of the command (with any trailing newline removed) is taken
+ as the argument value. The above escape sequences also apply in
+ backquotes.
</para>
<para>
</varlistentry>
<varlistentry>
- <term><literal>\copy</literal> <replaceable class="parameter">table</replaceable>
+ <term><literal>\copy <replaceable class="parameter">table</replaceable>
{ <literal>from</literal> | <literal>to</literal> }
<replaceable class="parameter">filename</replaceable> | stdin | stdout
[ <literal>with</literal> ]
[ <literal>oids</literal> ]
[ <literal>delimiter [as] </literal> '<replaceable class="parameter">character</replaceable>' ]
- [ <literal>null [as] </literal> '<replaceable class="parameter">string</replaceable>' ]
+ [ <literal>null [as] </literal> '<replaceable class="parameter">string</replaceable>' ]</literal>
</term>
<listitem>
<note>
<para>
- To reduce clutter, <literal>\df</> does not show datatype I/O
+ To reduce clutter, <literal>\df</> does not show data type I/O
functions. This is implemented by ignoring functions that accept
or return type <type>cstring</>.
</para>
<note>
<para>
If you want to see the lines on the screen as they are read you
- must set the variable <envar>ECHO</envar> to
+ must set the variable <varname>ECHO</varname> to
<literal>all</literal>.
</para>
</note>
</tip>
<note>
<para>
- See the description of the <envar>LO_TRANSACTION</envar>
+ See the description of the <varname>LO_TRANSACTION</varname>
variable for important information concerning all large object
operations.
</para>
<note>
<para>
- See the description of the <envar>LO_TRANSACTION</envar>
+ See the description of the <varname>LO_TRANSACTION</varname>
variable for important information concerning all large object
operations.
</para>
</tip>
<note>
<para>
- See the description of the <envar>LO_TRANSACTION</envar>
+ See the description of the <varname>LO_TRANSACTION</varname>
variable for important information concerning all large object
operations.
</para>
<term><literal>pager</literal></term>
<listitem>
<para>
- Toggles the use of a pager for query and psql help output. If the
+ Toggles the use of a pager for query and <application>psql</> help output. If the
environment variable <envar>PAGER</envar> is set, the output
is piped to the specified program. Otherwise a platform-dependent default (such as
<filename>more</filename>) is used.
such variables. A list of all specially treated variables follows.
<variablelist>
<varlistentry>
- <term><envar>DBNAME</envar></term>
+ <term><varname>DBNAME</varname></term>
<listitem>
<para>
The name of the database you are currently connected to. This is
</varlistentry>
<varlistentry>
- <term><envar>ECHO</envar></term>
+ <term><varname>ECHO</varname></term>
<listitem>
<para>
If set to <quote><literal>all</literal></quote>, all lines
</varlistentry>
<varlistentry>
- <term><envar>ECHO_HIDDEN</envar></term>
+ <term><varname>ECHO_HIDDEN</varname></term>
<listitem>
<para>
When this variable is set and a backslash command queries the
database, the query is first shown. This way you can study the
<productname>PostgreSQL</productname> internals and provide
similar functionality in your own programs. If you set the
- variable to the value <quote>noexec</quote>, the queries are
+ variable to the value <literal>noexec</literal>, the queries are
just shown but are not actually sent to the backend and
executed.
</para>
</varlistentry>
<varlistentry>
- <term><envar>ENCODING</envar></term>
+ <term><varname>ENCODING</varname></term>
<listitem>
<para>
The current client multibyte encoding. If you are not set up to
</varlistentry>
<varlistentry>
- <term><envar>HISTCONTROL</envar></term>
+ <term><varname>HISTCONTROL</varname></term>
<listitem>
<para>
If this variable is set to <literal>ignorespace</literal>,
</varlistentry>
<varlistentry>
- <term><envar>HISTSIZE</envar></term>
+ <term><varname>HISTSIZE</varname></term>
<listitem>
<para>
The number of commands to store in the command history. The
</varlistentry>
<varlistentry>
- <term><envar>HOST</envar></term>
+ <term><varname>HOST</varname></term>
<listitem>
<para>
The database server host you are currently connected to. This is
</varlistentry>
<varlistentry>
- <term><envar>IGNOREEOF</envar></term>
+ <term><varname>IGNOREEOF</varname></term>
<listitem>
<para>
- If unset, sending an EOF character (usually Control-D) to an
- interactive session of <application>psql</application> will
- terminate the application. If set to a numeric value, that many
- EOF characters are ignored before the application terminates.
- If the variable is set but has no numeric value, the default is
- 10.
+ If unset, sending an <acronym>EOF</> character (usually
+ <keycombo action="simul"><keycap>Control</><keycap>D</></>)
+ to an interactive session of <application>psql</application>
+ will terminate the application. If set to a numeric value,
+ that many <acronym>EOF</> characters are ignored before the
+ application terminates. If the variable is set but has no
+ numeric value, the default is 10.
</para>
<note>
<para>
</varlistentry>
<varlistentry>
- <term><envar>LASTOID</envar></term>
+ <term><varname>LASTOID</varname></term>
<listitem>
<para>
- The value of the last affected oid, as returned from an
+ The value of the last affected OID, as returned from an
<command>INSERT</command> or <command>lo_insert</command>
command. This variable is only guaranteed to be valid until
after the result of the next <acronym>SQL</acronym> command has
</varlistentry>
<varlistentry>
- <term><envar>LO_TRANSACTION</envar></term>
+ <term><varname>LO_TRANSACTION</varname></term>
<listitem>
<para>
If you use the <productname>PostgreSQL</productname> large
</varlistentry>
<varlistentry>
- <term><envar>ON_ERROR_STOP</envar></term>
+ <term><varname>ON_ERROR_STOP</varname></term>
<listitem>
<para>
By default, if non-interactive scripts encounter an error, such
</varlistentry>
<varlistentry>
- <term><envar>PORT</envar></term>
+ <term><varname>PORT</varname></term>
<listitem>
<para>
The database server port to which you are currently connected.
</varlistentry>
<varlistentry>
- <term><envar>PROMPT1</envar>, <envar>PROMPT2</envar>, <envar>PROMPT3</envar></term>
+ <term><varname>PROMPT1</varname></term>
+ <term><varname>PROMPT2</varname></term>
+ <term><varname>PROMPT3</varname></term>
<listitem>
<para>
These specify what the prompt <application>psql</application>
</varlistentry>
<varlistentry>
- <term><envar>QUIET</envar></term>
+ <term><varname>QUIET</varname></term>
<listitem>
<para>
This variable is equivalent to the command line option
</varlistentry>
<varlistentry>
- <term><envar>SINGLELINE</envar></term>
+ <term><varname>SINGLELINE</varname></term>
<listitem>
<para>
This variable is set by the command line option
</varlistentry>
<varlistentry>
- <term><envar>SINGLESTEP</envar></term>
+ <term><varname>SINGLESTEP</varname></term>
<listitem>
<para>
This variable is equivalent to the command line option
</varlistentry>
<varlistentry>
- <term><envar>USER</envar></term>
+ <term><varname>USER</varname></term>
<listitem>
<para>
The database user you are currently connected as. This is set
<para>
The prompts <application>psql</application> issues can be customized
- to your preference. The three variables <envar>PROMPT1</envar>,
- <envar>PROMPT2</envar>, and <envar>PROMPT3</envar> contain strings
+ to your preference. The three variables <varname>PROMPT1</varname>,
+ <varname>PROMPT2</varname>, and <varname>PROMPT3</varname> contain strings
and special escape sequences that describe the appearance of the
prompt. Prompt 1 is the normal prompt that is issued when
<application>psql</application> requests a new query. Prompt 2 is
</refsect3>
<refsect3>
- <title>Readline</title>
+ <title>Command-Line Editing</title>
<para>
- <application>psql</application> supports the readline and history
- libraries for convenient line editing and retrieval. The command
+ <application>psql</application> supports the <application>Readline</application>
+ library for convenient line editing and retrieval. The command
history is stored in a file named <filename>.psql_history</filename>
in your home directory and is reloaded when
<application>psql</application> starts up. Tab-completion is also
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PostgreSQL documentation
-->
as there is in <application>psql</>. To continue a command
across multiple lines, you must type backslash just before each
newline except the last one.
- Also, you won't have any of the conveniences of readline processing
+ Also, you won't have any of the conveniences of command-line editing
(no command history, for example).
</para>
</listitem>
<listitem>
<para>
- To quit the backend, type EOF (control-D, usually).
+ To quit the backend, type <acronym>EOF</> (<keycombo
+ action="simul"><keycap>Control</><keycap>D</></>, usually).
</para>
</listitem>
<!--
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PostgreSQL documentation
-->
<refsect1>
<title>Examples</title>
<para>
- Set DateStyle to its default value:
+ Set <varname>DateStyle</> to its default value:
<screen>
RESET DateStyle;
</para>
<para>
- Set Geqo to its default value:
+ Set <varname>geqo</> to its default value:
<screen>
RESET GEQO;
<!--
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PostgreSQL documentation
-->
(i.e., all combined rows that pass its ON condition), plus one copy of each
row in the left-hand table for which there was no right-hand row that
passed the ON condition. This left-hand row is extended to the full
- width of the joined table by inserting NULLs for the right-hand columns.
- Note that only the JOIN's own ON or USING condition is considered while
+ width of the joined table by inserting null values for the right-hand columns.
+ Note that only the <literal>JOIN</>'s own ON or USING condition is considered while
deciding which rows have matches. Outer ON or WHERE conditions are
applied afterwards.
</para>
</para>
<para>
- Optionally one may add the keyword DESC (descending)
- or ASC (ascending) after each column name in the ORDER BY clause.
- If not specified, ASC is assumed by default. Alternatively, a
- specific ordering operator name may be specified. ASC is equivalent
- to USING < and DESC is equivalent to USING >.
+ Optionally one may add the key word <literal>DESC</> (descending)
+ or <literal>ASC</> (ascending) after each column name in the
+ <literal>ORDER BY</> clause. If not specified, <literal>ASC</> is
+ assumed by default. Alternatively, a specific ordering operator
+ name may be specified. <literal>ASC</> is equivalent to
+ <literal>USING <</> and <literal>DESC</> is equivalent to
+ <literal>USING ></>.
</para>
<para>
<para>
The UNION operator computes the collection (set union) of the rows
returned by the queries involved.
- The two SELECTs that represent the direct operands of the UNION must
+ The two SELECT statements that represent the direct operands of the UNION must
produce the same number of columns, and corresponding columns must be
of compatible data types.
</para>
<para>
<productname>PostgreSQL</productname> allows one to omit
the <command>FROM</command> clause from a query. This feature
-was retained from the original PostQuel query language. It has
+was retained from the original PostQUEL query language. It has
a straightforward use to compute the results of simple expressions:
<programlisting>
4
</programlisting>
-Some other DBMSes cannot do this except by introducing a dummy one-row
+Some other SQL databases cannot do this except by introducing a dummy one-row
table to do the select from. A less obvious use is to abbreviate a
normal select from one or more tables:
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PostgreSQL documentation
-->
<variablelist>
<varlistentry>
- <term>DATESTYLE</term>
+ <term><varname>DATESTYLE</></term>
<listitem>
<para>
Choose the date/time representation style. Two separate
<variablelist>
<varlistentry>
- <term>ISO</term>
+ <term><literal>ISO</></term>
<listitem>
<para>
Use ISO 8601-style dates and times (<literal>YYYY-MM-DD
</varlistentry>
<varlistentry>
- <term>SQL</term>
+ <term><literal>SQL</></term>
<listitem>
<para>
Use Oracle/Ingres-style dates and times. Note that this
</varlistentry>
<varlistentry>
- <term>PostgreSQL</term>
+ <term><literal>PostgreSQL</></term>
<listitem>
<para>
Use traditional <productname>PostgreSQL</productname> format.
</varlistentry>
<varlistentry>
- <term>German</term>
+ <term><literal>German</></term>
<listitem>
<para>
Use <literal>dd.mm.yyyy</literal> for numeric date representations.
<variablelist>
<varlistentry>
- <term>European</term>
+ <term><literal>European</></term>
<listitem>
<para>
Use <literal>dd/mm/yyyy</literal> for numeric date representations.
</varlistentry>
<varlistentry>
- <term>NonEuropean</term>
- <term>US</term>
+ <term><literal>NonEuropean</></term>
+ <term><literal>US</></term>
<listitem>
<para>
Use <literal>mm/dd/yyyy</literal> for numeric date representations.
</para>
<para>
- There are several now-deprecated means for setting the datestyle
+ There are several now-deprecated means for setting the date style
in addition to the normal methods of setting it via <command>SET</> or
a configuration-file entry:
<simplelist>
</member>
<member>
Setting the client's <envar>PGDATESTYLE</envar> environment variable.
- If PGDATESTYLE is set in the frontend environment of a client
- based on libpq, libpq will automatically set DATESTYLE to the
- value of PGDATESTYLE during connection start-up. This is
+ If <envar>PGDATESTYLE</envar> is set in the frontend environment of a client
+ based on <application>libpq</>, <application>libpq</> will automatically set <varname>DATESTYLE</> to the
+ value of <envar>PGDATESTYLE</envar> during connection start-up. This is
equivalent to a manually issued <command>SET DATESTYLE</>.
</member>
</simplelist>
<para>
Shows the server-side multibyte encoding. (At present, this
parameter can be shown but not set, because the encoding is
- determined at initdb time.)
+ determined at <application>initdb</> time.)
</para>
</listitem>
</varlistentry>
<para>
If the <envar>PGTZ</envar> environment variable is set in the frontend
- environment of a client based on libpq, libpq will automatically
+ environment of a client based on <application>libpq</>, <application>libpq</> will automatically
<command>SET TIMEZONE</command> to the value of
<envar>PGTZ</envar> during connection start-up.
</para>
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/set_session_auth.sgml,v 1.6 2002/05/17 01:19:16 tgl Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/set_session_auth.sgml,v 1.7 2002/09/21 18:32:54 petere Exp $ -->
<refentry id="SQL-SET-SESSION-AUTHORIZATION">
<docinfo>
<date>2001-04-21</date>
The session user identifier may be changed only if the initial session
user (the <firstterm>authenticated user</firstterm>) had the
superuser privilege. Otherwise, the command is accepted only if it
- specifies the authenticated username.
+ specifies the authenticated user name.
</para>
<para>
<!--
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-->
<para>
<command>UNLISTEN</command>
is used to remove an existing <command>NOTIFY</command> registration.
- UNLISTEN cancels any existing registration of the current
+ <command>UNLISTEN</command> cancels any existing registration of the current
<productname>PostgreSQL</productname> session as a listener on the notify
condition <replaceable class="PARAMETER">notifyname</replaceable>.
The special condition wildcard <literal>*</literal> cancels all listener registrations
as a name up to 64 characters long.
</para>
<para>
- The backend does not complain if you UNLISTEN something you were not
+ The backend does not complain if you unlisten something you were not
listening for.
Each backend will automatically execute <command>UNLISTEN *</command> when
exiting.
</para>
<para>
- Once UNLISTEN has been executed, further NOTIFY commands will be
+ Once <command>UNLISTEN</> has been executed, further <command>NOTIFY</> commands will be
ignored:
<programlisting>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/vacuum.sgml,v 1.25 2002/04/23 02:07:16 tgl Exp $
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PostgreSQL documentation
-->
<para>
<command>VACUUM</command> reclaims storage occupied by deleted tuples.
In normal <productname>PostgreSQL</productname> operation, tuples that
- are DELETEd or obsoleted by UPDATE are not physically removed from
+ are deleted or obsoleted by UPDATE are not physically removed from
their table; they remain present until a <command>VACUUM</command> is
done. Therefore it's necessary to do <command>VACUUM</command>
periodically, especially on frequently-updated tables.
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/vacuumdb.sgml,v 1.25 2002/09/05 22:05:50 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/vacuumdb.sgml,v 1.26 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
<variablelist>
<varlistentry>
- <term>-d <replaceable class="parameter">dbname</replaceable></term>
- <term>--dbname <replaceable class="parameter">dbname</replaceable></term>
+ <term><option>-d <replaceable class="parameter">dbname</replaceable></option></term>
+ <term><option>--dbname <replaceable class="parameter">dbname</replaceable></option></term>
<listitem>
<para>
Specifies the name of the database to be cleaned or analyzed.
</varlistentry>
<varlistentry>
- <term>-a</term>
- <term>--all</term>
+ <term><option>-a</option></term>
+ <term><option>--all</option></term>
<listitem>
<para>
Vacuum all databases.
</varlistentry>
<varlistentry>
- <term>-f</term>
- <term>--full</term>
+ <term><option>-f</option></term>
+ <term><option>--full</option></term>
<listitem>
<para>
Perform <quote>full</quote> vacuuming.
</varlistentry>
<varlistentry>
- <term>-v</term>
- <term>--verbose</term>
+ <term><option>-v</option></term>
+ <term><option>--verbose</option></term>
<listitem>
<para>
Print detailed information during processing.
</varlistentry>
<varlistentry>
- <term>-z</term>
- <term>--analyze</term>
+ <term><option>-z</option></term>
+ <term><option>--analyze</option></term>
<listitem>
<para>
Calculate statistics for use by the optimizer.
</varlistentry>
<varlistentry>
- <term>-t <replaceable class="parameter">table</replaceable> [ (<replaceable class="parameter">column</replaceable> [,...]) ]</term>
- <term>--table <replaceable class="parameter">table</replaceable> [ (<replaceable class="parameter">column</replaceable> [,...]) ]</term>
+ <term><option>-t <replaceable class="parameter">table</replaceable> [ (<replaceable class="parameter">column</replaceable> [,...]) ]</option></term>
+ <term><option>--table <replaceable class="parameter">table</replaceable> [ (<replaceable class="parameter">column</replaceable> [,...]) ]</option></term>
<listitem>
<para>
Clean or analyze <replaceable class="parameter">table</replaceable> only.
<variablelist>
<varlistentry>
- <term>-h <replaceable class="parameter">host</replaceable></term>
- <term>--host <replaceable class="parameter">host</replaceable></term>
+ <term><option>-h <replaceable class="parameter">host</replaceable></></term>
+ <term><option>--host <replaceable class="parameter">host</replaceable></></term>
<listitem>
<para>
Specifies the host name of the machine on which the
</varlistentry>
<varlistentry>
- <term>-p <replaceable class="parameter">port</replaceable></term>
- <term>--port <replaceable class="parameter">port</replaceable></term>
+ <term><option>-p <replaceable class="parameter">port</replaceable></></term>
+ <term><option>--port <replaceable class="parameter">port</replaceable></></term>
<listitem>
<para>
Specifies the Internet TCP/IP port or local Unix domain socket file
</varlistentry>
<varlistentry>
- <term>-U <replaceable class="parameter">username</replaceable></term>
- <term>--username <replaceable class="parameter">username</replaceable></term>
+ <term><option>-U <replaceable class="parameter">username</replaceable></></term>
+ <term><option>--username <replaceable class="parameter">username</replaceable></></term>
<listitem>
<para>
User name to connect as
</varlistentry>
<varlistentry>
- <term>-W</term>
- <term>--password</term>
+ <term><option>-W</></term>
+ <term><option>--password</></term>
<listitem>
<para>
Force password prompt.
</varlistentry>
<varlistentry>
- <term>-e</term>
- <term>--echo</term>
+ <term><option>-e</></term>
+ <term><option>--echo</></term>
<listitem>
<para>
Echo the commands that <application>vacuumdb</application> generates
</varlistentry>
<varlistentry>
- <term>-q</term>
- <term>--quiet</term>
+ <term><option>-q</></term>
+ <term><option>--quiet</></term>
<listitem>
<para>
Do not display a response.
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/regress.sgml,v 1.27 2002/05/14 13:05:42 petere Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/regress.sgml,v 1.28 2002/09/21 18:32:53 petere Exp $ -->
<chapter id="regress">
<title id="regress-title">Regression Tests</title>
<para>
The parallel regression test starts quite a few processes under your
user ID. Presently, the maximum concurrency is twenty parallel test
- scripts, which means sixty processes --- there's a backend, a psql,
- and usually a shell parent process for the psql for each test script.
+ scripts, which means sixty processes --- there's a backend, a <application>psql</>,
+ and usually a shell parent process for the <application>psql</> for each test script.
So if your system enforces a per-user limit on the number of processes,
make sure this limit is at least seventy-five or so, else you may get
random-seeming failures in the parallel test. If you are not in
problem by providing alternative result files that together are
known to handle a large number of locales. For example, for the
<quote>char</quote> test, the expected file
- <filename>char.out</filename> handles the C and POSIX locales,
+ <filename>char.out</filename> handles the <literal>C</> and <literal>POSIX</> locales,
and the file <filename>char_1.out</filename> handles many other
locales. The regression test driver will automatically pick the
best file to match against when checking for success and for
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/release.sgml,v 1.159 2002/09/18 21:35:20 tgl Exp $
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-->
<appendix id="release">
</sect3>
<sect3>
- <title>PL/pgSQL</title>
+ <title><application>PL/pgSQL</></title>
<literallayout>
Now uses portals for SELECT loops, allowing huge result sets (Jan)
CURSOR and REFCURSOR support (Jan)
</sect3>
<sect3>
- <title>Psql</title>
+ <title><application>Psql</></title>
<literallayout>
\d displays indexes in unique, primary groupings (Christopher Kings-Lynne)
Allow trailing semicolons in backslash commands (Greg Sabino Mullane)
</sect3>
<sect3>
- <title>Libpq</title>
+ <title><application>Libpq</></title>
<literallayout>
New function PQescapeString() to escape quotes in command strings (Florian Weimer)
New function PQescapeBytea() escapes binary strings for use as SQL string literals
</sect3>
<sect3>
- <title>ECPG</title>
+ <title><application>ECPG</></title>
<literallayout>
EXECUTE ... INTO implemented (Christof Petig)
Multiple row descriptor support (e.g. CARDINALITY) (Christof Petig)
<listitem>
<para>
The previous C function manager did not
-handle
NULLs properly, nor did it support 64-bit <acronym>CPU</acronym>'s (Alpha). The new
+handle
null values properly, nor did it support 64-bit <acronym>CPU</acronym>'s (Alpha). The new
function manager does. You can continue using your old custom
functions, but you may want to rewrite them in the future to use the new
function manager call interface.
</term>
<listitem>
<para>
- SQL92 join syntax is now supported, though only as INNER JOINs
- for this release. JOIN, NATURAL JOIN, JOIN/USING, JOIN/ON are
- available, as are column correlation names.
+ SQL92 join syntax is now supported, though only as
+ <literal>INNER JOIN</> for this release. <literal>JOIN</>,
+ <literal>NATURAL JOIN</>, <literal>JOIN</>/<literal>USING</>,
+ and <literal>JOIN</>/<literal>ON</> are available, as are
+ column correlation names.
</para>
</listitem>
</varlistentry>
<listitem>
<para>
-We have optional multiple-byte character set support from Tatsuo Iishi
+We have optional multiple-byte character set support from Tatsuo Ishii
to complement our existing locale support.
</para>
</listitem>
</para>
<para>
- The "random" results in the random test should cause the "random" test
- to be "failed", since the regression tests are evaluated using a simple
- diff. However, "random" does not seem to produce random results on my
- test machine (Linux/gcc/i686).
+ The <quote>random</> results in the random test should cause the
+ <quote>random</quote> test to be <quote>failed</quote>, since the
+ regression tests are evaluated using a simple diff. However,
+ <quote>random</> does not seem to produce random results on my test
+ machine (Linux/<application>gcc</>/i686).
</para>
<sect2>
</programlisting>
</para>
<para>
-If you are loading an older binary copy or non-stdout copy, there is no
+If you are loading an older binary copy or non-<systemitem>stdout</> copy, there is no
end-of-data character, and hence no conversion necessary.
<programlisting>
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/rules.sgml,v 1.23 2002/04/19 23:13:53 tgl Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/rules.sgml,v 1.24 2002/09/21 18:32:53 petere Exp $ -->
<Chapter Id="rules">
<Title>The Rule System</Title>
<Para>
DELETE queries don't need a target list because they don't
- produce any result. In fact the planner will add a special CTID
+ produce any result. In fact the planner will add a special <acronym>CTID</>
entry to the empty target list. But this is after the rule
system and will be discussed later. For the rule system the
target list is empty.
expressions from the SET attribute = expression part of the query.
The planner will add missing columns by inserting expressions that
copy the values from the old row into the new one. And it will add
- the special CTID entry just as for DELETE too.
+ the special <acronym>CTID</> entry just as for DELETE too.
</Para>
<Para>
<Para>
To resolve this problem, another entry is added to the target list
- in UPDATE (and also in DELETE) statements: the current tuple ID (CTID).
+ in UPDATE (and also in DELETE) statements: the current tuple ID (<acronym>CTID</>).
This is a system attribute containing the file
block number and position in the block for the row. Knowing the table,
- the CTID can be used to retrieve the original t1 row to be updated.
- After adding the CTID to the target list, the query actually looks like
+ the <acronym>CTID</> can be used to retrieve the original t1 row to be updated.
+ After adding the <acronym>CTID</> to the target list, the query actually looks like
<ProgramListing>
SELECT t1.a, t2.b, t1.ctid FROM t1, t2 WHERE t1.a = t2.a;
</ProgramListing>
- Now another detail of <ProductName>PostgreSQL</ProductName> enters the
- stage. At this moment, table rows aren't overwritten and this is why
- ABORT TRANSACTION is fast. In an UPDATE, the new result row is inserted
- into the table (after stripping CTID) and in the tuple header of the row
- that CTID pointed to the cmax and xmax entries are set to the current
- command counter and current transaction ID. Thus the old row is hidden
- and after the transaction committed the vacuum cleaner can really move
- it out.
+ Now another detail of <ProductName>PostgreSQL</ProductName> enters
+ the stage. At this moment, table rows aren't overwritten and this
+ is why ABORT TRANSACTION is fast. In an UPDATE, the new result row
+ is inserted into the table (after stripping <acronym>CTID</>) and
+ in the tuple header of the row that <acronym>CTID</> pointed to
+ the <literal>cmax</> and <literal>xmax</> entries are set to the
+ current command counter and current transaction ID. Thus the old
+ row is hidden and after the transaction committed the vacuum
+ cleaner can really move it out.
</Para>
<Para>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.137 2002/09/18 20:09:32 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.138 2002/09/21 18:32:53 petere Exp $
-->
<Chapter Id="runtime">
<programlisting>
env PGOPTIONS='-c geqo=off' psql
</programlisting>
- (This works for any libpq-based client application, not just
+ (This works for any <application>libpq</>-based client application, not just
<application>psql</application>.) Note that this won't work for
options that are fixed when the server is started, such as the port
number.
<listitem>
<para>
Determines whether <command>EXPLAIN VERBOSE</> uses the indented
- or non-indented format for displaying detailed querytree dumps.
+ or non-indented format for displaying detailed query-tree dumps.
</para>
</listitem>
</varlistentry>
<term><varname>LOG_PID</varname> (<type>boolean</type>)</term>
<listitem>
<para>
- Prefixes each server message in the logfile with the process ID of
+ Prefixes each server message in the log file with the process ID of
the backend process. This is useful to sort out which messages
pertain to which connection. The default is off. This parameter
- does not affect messages logged via syslog(), which always contain
+ does not affect messages logged via <application>syslog</>, which always contain
the process ID.
</para>
</listitem>
<listitem>
<para>
This variable specifies the order in which namespaces are searched
- when an object (table, datatype, function, etc) is referenced by a
+ when an object (table, data type, function, etc) is referenced by a
simple name with no schema component. When there are objects of
identical names in different namespaces, the one found first
in the search path is used. An object that is not in any of the
However, filtered forms in <productname>Microsoft
Access</productname> generate queries that appear to use
<literal><replaceable>expr</> = NULL</literal> to test for
- NULLs, so if you use that interface to access the database you
+ null values, so if you use that interface to access the database you
might want to turn this option on. Since expressions of the
form <literal><replaceable>expr</> = NULL</literal> always
return NULL (using the correct interpretation) they are not
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/syntax.sgml,v 1.69 2002/09/12 22:05:36 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/syntax.sgml,v 1.70 2002/09/21 18:32:54 petere Exp $
-->
<chapter id="sql-syntax">
<row>
<entry><token>IS</token></entry>
<entry></entry>
- <entry>test for TRUE, FALSE, UNKNOWN, NULL</entry>
+ <entry><literal>IS TRUE</>, <literal>IS FALSE</>, <literal>IS UNKNOWN</>, <literal>IS NULL</></entry>
</row>
<row>
<entry><token>ISNULL</token></entry>
<entry></entry>
- <entry>test for NULL</entry>
+ <entry>test for null</entry>
</row>
<row>
<entry><token>NOTNULL</token></entry>
<entry></entry>
- <entry>test for NOT NULL</entry>
+ <entry>test for not null</entry>
</row>
<row>
<para>
The first form of aggregate expression invokes the aggregate
across all input rows for which the given expression yields a
- non-NULL value. (Actually, it is up to the aggregate function
- whether to ignore NULLs or not --- but all the standard ones do.)
+ non-null value. (Actually, it is up to the aggregate function
+ whether to ignore null values or not --- but all the standard ones do.)
The second form is the same as the first, since
<literal>ALL</literal> is the default. The third form invokes the
- aggregate for all distinct non-NULL values of the expression found
+ aggregate for all distinct non-null values of the expression found
in the input rows. The last form invokes the aggregate once for
- each input row regardless of NULL or non-NULL values; since no
+ each input row regardless of null or non-null values; since no
particular input value is specified, it is generally only useful
for the <function>count()</function> aggregate function.
</para>
<para>
For example, <literal>count(*)</literal> yields the total number
of input rows; <literal>count(f1)</literal> yields the number of
- input rows in which <literal>f1</literal> is non-NULL;
+ input rows in which <literal>f1</literal> is non-null;
<literal>count(distinct f1)</literal> yields the number of
- distinct non-NULL values of <literal>f1</literal>.
+ distinct non-null values of <literal>f1</literal>.
</para>
<para>
to the type that a value expression must produce (for example, when it is
assigned to a table column); the system will automatically apply a
type cast in such cases. However, automatic casting is only done for
- cast functions that are marked <quote>okay to apply implicitly</>
+ cast functions that are marked <quote>OK to apply implicitly</>
in the system catalogs. Other cast functions must be invoked with
explicit casting syntax. This restriction is intended to prevent
surprising conversions from being applied silently.
It is an error to use a query that
returns more than one row or more than one column as a scalar subquery.
(But if, during a particular execution, the subquery returns no rows,
- there is no error; the scalar result is taken to be NULL.)
+ there is no error; the scalar result is taken to be null.)
The subquery can refer to variables from the surrounding query,
which will act as constants during any one evaluation of the subquery.
See also <xref linkend="functions-subquery">.
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/trigger.sgml,v 1.24 2002/08/22 00:01:40 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/trigger.sgml,v 1.25 2002/09/21 18:32:54 petere Exp $
-->
<chapter id="triggers">
<title>Triggers</title>
<para>
- <productname>PostgreSQL</productname> has various server-side function
- interfaces. Server-side functions can be written in SQL, PL/pgSQL,
- Tcl, or C. Trigger functions can be written in any of these
- languages except SQL. Note that statement-level trigger events are not
- supported in the current version. You can currently specify BEFORE or
- AFTER on INSERT, DELETE or UPDATE of a tuple as a trigger event.
+ <productname>PostgreSQL</productname> has various server-side
+ function interfaces. Server-side functions can be written in SQL,
+ C, or any defined procedural language. Trigger functions can be
+ written in C and most procedural languages, but not in SQL. Note that
+ statement-level trigger events are not supported in the current
+ version. You can currently specify BEFORE or AFTER on INSERT,
+ DELETE or UPDATE of a tuple as a trigger event.
</para>
<sect1 id="trigger-definition">
<para>
If a trigger event occurs, the trigger manager (called by the Executor)
- sets up a TriggerData information structure (described below) and calls
+ sets up a <structname>TriggerData</> information structure (described below) and calls
the trigger function to handle the event.
</para>
The trigger function must be defined before the trigger itself can be
created. The trigger function must be declared as a
function taking no arguments and returning type <literal>trigger</>.
- (The trigger function receives its input through a TriggerData
+ (The trigger function receives its input through a <structname>TriggerData</>
structure, not in the form of ordinary function arguments.)
If the function is written in C, it must use the <quote>version 1</>
function manager interface.
<para>
The syntax for creating triggers is:
+<programlisting>
CREATE TRIGGER <replaceable>trigger</replaceable> [ BEFORE | AFTER ] [ INSERT | DELETE | UPDATE [ OR ... ] ]
ON <replaceable>relation</replaceable> FOR EACH [ ROW | STATEMENT ]
EXECUTE PROCEDURE <replaceable>procedure</replaceable>
(<replaceable>args</replaceable>);
- </programlisting>
+</programlisting>
where the arguments are:
<term><replaceable>args</replaceable></term>
<listitem>
<para>
- The arguments passed to the function in the TriggerData structure.
+ The arguments passed to the function in the <structname>TriggerData</> structure.
This is either empty or a list of one or more simple literal
constants (which will be passed to the function as strings).
</para>
triggers with similar requirements to call the same function.
As an example, there could be a generalized trigger
function that takes as its arguments two field names and puts the
- current user in one and the current timestamp in the other.
+ current user in one and the current time stamp in the other.
Properly written, this trigger function would be independent of
the specific table it is triggering on. So the same function
could be used for INSERT events on any table with suitable fields,
</para>
<para>
- Trigger functions return a HeapTuple to the calling Executor. The return
+ Trigger functions return a <structname>HeapTuple</> to the calling executor. The return
value is ignored for triggers fired AFTER an operation,
but it allows BEFORE triggers to:
<itemizedlist>
<listitem>
<para>
- Return NULL to skip the operation for the current tuple (and so the
- tuple will not be inserted/updated/deleted).
+ Return a <symbol>NULL</> pointer to skip the operation for the
+ current tuple (and so the tuple will not be
+ inserted/updated/deleted).
</para>
</listitem>
</para>
<para>
- If more than one trigger
- is defined for the same event on the same relation, the triggers will
- be fired in alphabetical order by name. In the case of BEFORE triggers,
- the possibly-modified tuple returned by each trigger becomes the input
- to the next trigger. If any BEFORE trigger returns NULL, the operation
- is abandoned and subsequent triggers are not fired.
+ If more than one trigger is defined for the same event on the same
+ relation, the triggers will be fired in alphabetical order by
+ name. In the case of BEFORE triggers, the possibly-modified tuple
+ returned by each trigger becomes the input to the next trigger.
+ If any BEFORE trigger returns <symbol>NULL</>, the operation is
+ abandoned and subsequent triggers are not fired.
</para>
<para>
<para>
The interface described here applies for
<productname>PostgreSQL</productname> 7.1 and later.
- Earlier versions passed the TriggerData pointer in a global
- variable CurrentTriggerData.
+ Earlier versions passed the <structname>TriggerData</> pointer in a global
+ variable <varname>CurrentTriggerData</>.
</para>
</note>
<para>
When a function is called by the trigger manager, it is not passed any
normal parameters, but it is passed a <quote>context</> pointer pointing to a
- TriggerData structure. C functions can check whether they were called
+ <structname>TriggerData</> structure. C functions can check whether they were called
from the trigger manager or not by executing the macro
<literal>CALLED_AS_TRIGGER(fcinfo)</literal>, which expands to
- ((fcinfo)->context != NULL && IsA((fcinfo)->context, TriggerData))
- </programlisting>
- If this returns TRUE, then it is safe to cast fcinfo->context to type
+<programlisting>
+((fcinfo)->context != NULL && IsA((fcinfo)->context, TriggerData))
+</programlisting>
+ If this returns true, then it is safe to cast <literal>fcinfo->context</> to type
<literal>TriggerData *</literal> and make use of the pointed-to
- TriggerData structure.
- The function must <emphasis>not</emphasis> alter the TriggerData
+ <structname>TriggerData</> structure.
+ The function must <emphasis>not</emphasis> alter the <structname>TriggerData</>
structure or any of the data it points to.
</para>
<variablelist>
<varlistentry>
- <term>type</term>
+ <term><structfield>type</></term>
<listitem>
<para>
Always <literal>T_TriggerData</literal> if this is a trigger event.
</varlistentry>
<varlistentry>
- <term>tg_event</term>
+ <term><structfield>tg_event</></term>
<listitem>
<para>
describes the event for which the function is called. You may use the
</varlistentry>
<varlistentry>
- <term>tg_relation</term>
+ <term><structfield>tg_relation</></term>
<listitem>
<para>
- is a pointer to structure describing the triggered relation. Look at
- src/include/utils/rel.h for details about this structure. The most
- interesting things are tg_relation->rd_att (descriptor of the relation
- tuples) and tg_relation->rd_rel->relname (relation's name. This is not
- char*, but NameData. Use SPI_getrelname(tg_relation) to get char* if
- you need a copy of name).
+ is a pointer to structure describing the triggered
+ relation. Look at <filename>utils/rel.h</> for details about
+ this structure. The most interesting things are
+ <literal>tg_relation->rd_att</> (descriptor of the relation
+ tuples) and <literal>tg_relation->rd_rel->relname</>
+ (relation's name. This is not <type>char*</>, but
+ <type>NameData</>. Use
+ <literal>SPI_getrelname(tg_relation)</> to get <type>char*</> if you
+ need a copy of the name).
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>tg_trigtuple</term>
+ <term><structfield>tg_trigtuple</></term>
<listitem>
<para>
is a pointer to the tuple for which the trigger is fired. This is the tuple
</varlistentry>
<varlistentry>
- <term>tg_newtuple</term>
+ <term><structfield>tg_newtuple</></term>
<listitem>
<para>
- is a pointer to the new version of tuple if UPDATE and NULL if this is
+ is a pointer to the new version of tuple if UPDATE and <symbol>NULL</> if this is
for an INSERT or a DELETE. This is what you are to return to Executor if
UPDATE and you don't want to replace this tuple with another one or skip
the operation.
</varlistentry>
<varlistentry>
- <term>tg_trigger</term>
+ <term><structfield>tg_trigger</></term>
<listitem>
<para>
- is pointer to structure Trigger defined in src/include/utils/rel.h:
+ is pointer to structure <structname>Trigger</> defined in <filename>utils/rel.h</>:
+<programlisting>
typedef struct Trigger
{
Oid tgoid;
int16 tgattr[FUNC_MAX_ARGS];
char **tgargs;
} Trigger;
- </programlisting>
+</programlisting>
- where
- tgname is the trigger's name, tgnargs is number of arguments in tgargs,
- tgargs is an array of pointers to the arguments specified in the CREATE
- TRIGGER statement. Other members are for internal use only.
+ where <structfield>tgname</> is the trigger's name,
+ <structfield>tgnargs</> is number of arguments in
+ <structfield>tgargs</>, <structfield>tgargs</> is an array of
+ pointers to the arguments specified in the CREATE TRIGGER
+ statement. Other members are for internal use only.
</para>
</listitem>
</varlistentry>
changes made by the query itself (via SQL-function, SPI-function, triggers)
are invisible to the query scan. For example, in query
+<programlisting>
INSERT INTO a SELECT * FROM a;
- </programlisting>
+</programlisting>
tuples inserted are invisible for SELECT scan. In effect, this
duplicates the database table within itself (subject to unique index
<para>
This is true for triggers as well so, though a tuple being inserted
- (tg_trigtuple) is not visible to queries in a BEFORE trigger, this tuple
+ (<structfield>tg_trigtuple</>) is not visible to queries in a BEFORE trigger, this tuple
(just inserted) is visible to queries in an AFTER trigger, and to queries
in BEFORE/AFTER triggers fired after this!
</para>
</para>
<para>
- Here is a very simple example of trigger usage. Function trigf reports
- the number of tuples in the triggered relation ttest and skips the
- operation if the query attempts to insert NULL into x (i.e - it acts as a
- NOT NULL constraint but doesn't abort the transaction).
+ Here is a very simple example of trigger usage. Function <function>trigf</> reports
+ the number of tuples in the triggered relation <literal>ttest</> and skips the
+ operation if the query attempts to insert a null value into x (i.e - it acts as a
+ not-null constraint but doesn't abort the transaction).
-#include "executor/spi.h" /* this is what you need to work with SPI */
-#include "commands/trigger.h" /* -"- and triggers */
+<programlisting>
+#include "executor/spi.h" /* this is what you need to work with SPI */
+#include "commands/trigger.h" /* -"- and triggers */
extern Datum trigf(PG_FUNCTION_ARGS);
Datum
trigf(PG_FUNCTION_ARGS)
{
- TriggerData *trigdata = (TriggerData *) fcinfo->context;
- TupleDesc tupdesc;
- HeapTuple rettuple;
- char *when;
- bool checknull = false;
- bool isnull;
- int ret, i;
-
- /* Make sure trigdata is pointing at what I expect */
- if (!CALLED_AS_TRIGGER(fcinfo))
- elog(ERROR, "trigf: not fired by trigger manager");
-
- /* tuple to return to Executor */
- if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
- rettuple = trigdata->tg_newtuple;
- else
- rettuple = trigdata->tg_trigtuple;
-
- /* check for NULLs ? */
- if (!TRIGGER_FIRED_BY_DELETE(trigdata->tg_event) &&
- TRIGGER_FIRED_BEFORE(trigdata->tg_event))
- checknull = true;
-
- if (TRIGGER_FIRED_BEFORE(trigdata->tg_event))
- when = "before";
- else
- when = "after ";
-
- tupdesc = trigdata->tg_relation->rd_att;
-
- /* Connect to SPI manager */
- if ((ret = SPI_connect()) < 0)
- elog(INFO, "trigf (fired %s): SPI_connect returned %d", when, ret);
-
- /* Get number of tuples in relation */
- ret = SPI_exec("SELECT count(*) FROM ttest", 0);
-
- if (ret < 0)
- elog(NOTICE, "trigf (fired %s): SPI_exec returned %d", when, ret);
-
- /* count(*) returns int8 as of PG 7.2, so be careful to convert */
- i = (int) DatumGetInt64(SPI_getbinval(SPI_tuptable->vals[0],
- SPI_tuptable->tupdesc,
- 1,
- &isnull));
-
- elog (NOTICE, "trigf (fired %s): there are %d tuples in ttest", when, i);
-
- SPI_finish();
-
- if (checknull)
- {
- (void) SPI_getbinval(rettuple, tupdesc, 1, &isnull);
- if (isnull)
- rettuple = NULL;
- }
-
- return PointerGetDatum(rettuple);
+ TriggerData *trigdata = (TriggerData *) fcinfo->context;
+ TupleDesc tupdesc;
+ HeapTuple rettuple;
+ char *when;
+ bool checknull = false;
+ bool isnull;
+ int ret, i;
+
+ /* Make sure trigdata is pointing at what I expect */
+ if (!CALLED_AS_TRIGGER(fcinfo))
+ elog(ERROR, "trigf: not fired by trigger manager");
+
+ /* tuple to return to Executor */
+ if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
+ rettuple = trigdata->tg_newtuple;
+ else
+ rettuple = trigdata->tg_trigtuple;
+
+ /* check for null values */
+ if (!TRIGGER_FIRED_BY_DELETE(trigdata->tg_event)
+ && TRIGGER_FIRED_BEFORE(trigdata->tg_event))
+ checknull = true;
+
+ if (TRIGGER_FIRED_BEFORE(trigdata->tg_event))
+ when = "before";
+ else
+ when = "after ";
+
+ tupdesc = trigdata->tg_relation->rd_att;
+
+ /* Connect to SPI manager */
+ if ((ret = SPI_connect()) < 0)
+ elog(INFO, "trigf (fired %s): SPI_connect returned %d", when, ret);
+
+ /* Get number of tuples in relation */
+ ret = SPI_exec("SELECT count(*) FROM ttest", 0);
+
+ if (ret < 0)
+ elog(NOTICE, "trigf (fired %s): SPI_exec returned %d", when, ret);
+
+ /* count(*) returns int8 as of PG 7.2, so be careful to convert */
+ i = (int) DatumGetInt64(SPI_getbinval(SPI_tuptable->vals[0],
+ SPI_tuptable->tupdesc,
+ 1,
+ &isnull));
+
+ elog (NOTICE, "trigf (fired %s): there are %d tuples in ttest", when, i);
+
+ SPI_finish();
+
+ if (checknull)
+ {
+ (void) SPI_getbinval(rettuple, tupdesc, 1, &isnull);
+ if (isnull)
+ rettuple = NULL;
+ }
+
+ return PointerGetDatum(rettuple);
}
- </programlisting>
+</programlisting>
</para>
<para>
Now, compile and create the trigger function:
+<programlisting>
CREATE FUNCTION trigf () RETURNS TRIGGER AS
-'...path_to_so' LANGUAGE 'C';
+'...path_to_so' LANGUAGE C;
CREATE TABLE ttest (x int4);
- </programlisting>
+</programlisting>
+<programlisting>
vac=> CREATE TRIGGER tbefore BEFORE INSERT OR UPDATE OR DELETE ON ttest
FOR EACH ROW EXECUTE PROCEDURE trigf();
CREATE
-- Insertion skipped and AFTER trigger is not fired
vac=> SELECT * FROM ttest;
-x
--
+ x
+---
(0 rows)
vac=> INSERT INTO ttest VALUES (1);
remember what we said about visibility.
INSERT 167793 1
vac=> SELECT * FROM ttest;
-x
--
-1
+ x
+---
+ 1
(1 row)
vac=> INSERT INTO ttest SELECT x * 2 FROM ttest;
remember what we said about visibility.
INSERT 167794 1
vac=> SELECT * FROM ttest;
-x
--
-1
-2
+ x
+---
+ 1
+ 2
(2 rows)
-vac=> UPDATE ttest SET x = null WHERE x = 2;
+vac=> UPDATE ttest SET x = NULL WHERE x = 2;
INFO: trigf (fired before): there are 2 tuples in ttest
UPDATE 0
vac=> UPDATE ttest SET x = 4 WHERE x = 2;
INFO: trigf (fired after ): there are 2 tuples in ttest
UPDATE 1
vac=> SELECT * FROM ttest;
-x
--
-1
-4
+ x
+---
+ 1
+ 4
(2 rows)
vac=> DELETE FROM ttest;
remember what we said about visibility.
DELETE 2
vac=> SELECT * FROM ttest;
-x
--
+ x
+---
(0 rows)
- </programlisting>
+</programlisting>
</para>
</sect1>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/xaggr.sgml,v 1.16 2002/01/07 02:29:14 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/xaggr.sgml,v 1.17 2002/09/21 18:32:54 petere Exp $
-->
<chapter id="xaggr">
<para>
Another bit of default behavior for a <quote>strict</> transition function
is that the previous state value is retained unchanged whenever a
- NULL input value is encountered. Thus, NULLs are ignored. If you
+ NULL input value is encountered. Thus, null values are ignored. If you
need some other behavior for NULL inputs, just define your transition
function as non-strict, and code it to test for NULL inputs and do
whatever is needed.
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/xfunc.sgml,v 1.60 2002/09/01 16:28:05 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/xfunc.sgml,v 1.61 2002/09/21 18:32:54 petere Exp $
-->
<chapter id="xfunc">
meaning that
the system should automatically assume a NULL result if any input
value is NULL. By doing this, we avoid having to check for NULL inputs
- in the function code. Without this, we'd have to check for NULLs
+ in the function code. Without this, we'd have to check for null values
explicitly, for example by checking for a null pointer for each
pass-by-reference argument. (For pass-by-value arguments, we don't
even have a way to check!)
either base (scalar) data types, or composite (multi-column) data types.
The API is split into two main components: support for returning
composite data types, and support for returning multiple rows
- (set returning functions or SRFs).
+ (set returning functions or <acronym>SRF</>s).
</para>
<para>
</para>
<sect3>
- <title>Returning Tuples (Composite Types)</title>
+ <title>Returning Rows (Composite Types)</title>
<para>
The Table Function API support for returning composite data types
- (or tuples) starts with the AttInMetadata struct. This struct holds
- arrays of individual attribute information needed to create a tuple from
- raw C strings. It also saves a pointer to the TupleDesc. The information
- carried here is derived from the TupleDesc, but it is stored here to
- avoid redundant CPU cycles on each call to a Table Function. In the
- case of a function returning a set, the AttInMetadata struct should be
- computed once during the first call and saved for re-use in later calls.
+ (or rows) starts with the <structname>AttInMetadata</>
+ structure. This structure holds arrays of individual attribute
+ information needed to create a row from raw C strings. It also
+ saves a pointer to the <structname>TupleDesc</>. The information
+ carried here is derived from the <structname>TupleDesc</>, but it
+ is stored here to avoid redundant CPU cycles on each call to a
+ table function. In the case of a function returning a set, the
+ <structname>AttInMetadata</> structure should be computed
+ once during the first call and saved for re-use in later calls.
<programlisting>
typedef struct AttInMetadata
{
int32 *atttypmods;
} AttInMetadata;
</programlisting>
- To assist you in populating this struct, several functions and a macro
+ </para>
+
+ <para>
+ To assist you in populating this structure, several functions and a macro
are available. Use
<programlisting>
TupleDesc RelationNameGetTupleDesc(const char *relname)
</programlisting>
- to get a TupleDesc based on a specified relation, or
+ to get a <structname>TupleDesc</> based on a specified relation, or
<programlisting>
TupleDesc TypeGetTupleDesc(Oid typeoid, List *colaliases)
</programlisting>
- to get a TupleDesc based on a type OID. This can be used to
- get a TupleDesc for a base (scalar) or composite (relation) type. Then
+ to get a <structname>TupleDesc</> based on a type OID. This can
+ be used to get a <structname>TupleDesc</> for a base (scalar) or
+ composite (relation) type. Then
<programlisting>
AttInMetadata *TupleDescGetAttInMetadata(TupleDesc tupdesc)
</programlisting>
- will return a pointer to an AttInMetadata struct, initialized based on
- the given TupleDesc. AttInMetadata can be used in conjunction with
- C strings to produce a properly formed tuple. The metadata is stored here
- to avoid redundant work across multiple calls.
+ will return a pointer to an <structname>AttInMetadata</>,
+ initialized based on the given
+ <structname>TupleDesc</>. <structname>AttInMetadata</> can be
+ used in conjunction with C strings to produce a properly formed
+ tuple. The metadata is stored here to avoid redundant work across
+ multiple calls.
</para>
<para>
To return a tuple you must create a tuple slot based on the
- TupleDesc. You can use
+ <structname>TupleDesc</>. You can use
<programlisting>
TupleTableSlot *TupleDescGetSlot(TupleDesc tupdesc)
</programlisting>
to initialize this tuple slot, or obtain one through other (user provided)
- means. The tuple slot is needed to create a Datum for return by the
+ means. The tuple slot is needed to create a <type>Datum</> for return by the
function. The same slot can (and should) be re-used on each call.
</para>
<para>
- After constructing an AttInMetadata structure,
+ After constructing an <structname>AttInMetadata</> structure,
<programlisting>
HeapTuple BuildTupleFromCStrings(AttInMetadata *attinmeta, char **values)
</programlisting>
- can be used to build a HeapTuple given user data in C string form.
- "values" is an array of C strings, one for each attribute of the return
- tuple. Each C string should be in the form expected by the input function
- of the attribute data type. In order to return a NULL value for
- one of the attributes, the corresponding pointer in the "values" array
- should be set to NULL. This function will need to be called again
- for each tuple you return.
+ can be used to build a <structname>HeapTuple</> given user data
+ in C string form. "values" is an array of C strings, one for
+ each attribute of the return tuple. Each C string should be in
+ the form expected by the input function of the attribute data
+ type. In order to return a null value for one of the attributes,
+ the corresponding pointer in the <parameter>values</> array
+ should be set to <symbol>NULL</>. This function will need to
+ be called again for each tuple you return.
</para>
<para>
- Building a tuple via TupleDescGetAttInMetadata and BuildTupleFromCStrings
- is only convenient if your function naturally computes the values to
- be returned as text strings. If your code naturally computes the
- values as a set of Datums, you should instead use the underlying
- heap_formtuple routine to convert the Datums directly into a tuple.
- You will still need the TupleDesc and a TupleTableSlot, but not
- AttInMetadata.
+ Building a tuple via <function>TupleDescGetAttInMetadata</> and
+ <function>BuildTupleFromCStrings</> is only convenient if your
+ function naturally computes the values to be returned as text
+ strings. If your code naturally computes the values as a set of
+ Datums, you should instead use the underlying
+ <function>heap_formtuple</> routine to convert the
+ <type>Datum</type>s directly into a tuple. You will still need
+ the <structname>TupleDesc</> and a <structname>TupleTableSlot</>,
+ but not <structname>AttInMetadata</>.
</para>
<para>
Once you have built a tuple to return from your function, the tuple must
- be converted into a Datum. Use
+ be converted into a <type>Datum</>. Use
<programlisting>
TupleGetDatum(TupleTableSlot *slot, HeapTuple tuple)
</programlisting>
- to get a Datum given a tuple and a slot. This Datum can be returned
- directly if you intend to return just a single row, or it can be used
- as the current return value in a set-returning function.
+ to get a <type>Datum</> given a tuple and a slot. This
+ <type>Datum</> can be returned directly if you intend to return
+ just a single row, or it can be used as the current return value
+ in a set-returning function.
</para>
<para>
<title>Returning Sets</title>
<para>
- A set-returning function (SRF) is normally called once for each item it
- returns. The SRF must therefore save enough state to remember what it
- was doing and return the next item on each call. The Table Function API
- provides the FuncCallContext struct to help control this process.
- <literal>fcinfo->flinfo->fn_extra</> is used to
- hold a pointer to FuncCallContext across calls.
+ A set-returning function (<acronym>SRF</>) is normally called
+ once for each item it returns. The <acronym>SRF</> must
+ therefore save enough state to remember what it was doing and
+ return the next item on each call. The Table Function API
+ provides the <structname>FuncCallContext</> structure to help
+ control this process. <literal>fcinfo->flinfo->fn_extra</>
+ is used to hold a pointer to <structname>FuncCallContext</>
+ across calls.
<programlisting>
typedef struct
{
- /*
- * Number of times we've been called before.
- *
- * call_cntr is initialized to 0 for you by SRF_FIRSTCALL_INIT(), and
- * incremented for you every time SRF_RETURN_NEXT() is called.
- */
- uint32 call_cntr;
-
- /*
- * OPTIONAL maximum number of calls
- *
- * max_calls is here for convenience ONLY and setting it is OPTIONAL.
- * If not set, you must provide alternative means to know when the
- * function is done.
- */
- uint32 max_calls;
-
- /*
- * OPTIONAL pointer to result slot
- *
- * slot is for use when returning tuples (i.e. composite data types)
- * and is not needed when returning base (i.e. scalar) data types.
- */
- TupleTableSlot *slot;
-
- /*
- * OPTIONAL pointer to misc user provided context info
- *
- * user_fctx is for use as a pointer to your own struct to retain
- * arbitrary context information between calls for your function.
- */
- void *user_fctx;
-
- /*
- * OPTIONAL pointer to struct containing arrays of attribute type input
- * metainfo
- *
- * attinmeta is for use when returning tuples (i.e. composite data types)
- * and is not needed when returning base (i.e. scalar) data types. It
- * is ONLY needed if you intend to use BuildTupleFromCStrings() to create
- * the return tuple.
- */
- AttInMetadata *attinmeta;
-
- /*
- * memory context used for structures which must live for multiple calls
- *
- * multi_call_memory_ctx is set by SRF_FIRSTCALL_INIT() for you, and used
- * by SRF_RETURN_DONE() for cleanup. It is the most appropriate memory
- * context for any memory that is to be re-used across multiple calls
- * of the SRF.
- */
- MemoryContext multi_call_memory_ctx;
-
-} FuncCallContext;
+ /*
+ * Number of times we've been called before.
+ *
+ * call_cntr is initialized to 0 for you by SRF_FIRSTCALL_INIT(), and
+ * incremented for you every time SRF_RETURN_NEXT() is called.
+ */
+ uint32 call_cntr;
+
+ /*
+ * OPTIONAL maximum number of calls
+ *
+ * max_calls is here for convenience ONLY and setting it is OPTIONAL.
+ * If not set, you must provide alternative means to know when the
+ * function is done.
+ */
+ uint32 max_calls;
+
+ /*
+ * OPTIONAL pointer to result slot
+ *
+ * slot is for use when returning tuples (i.e. composite data types)
+ * and is not needed when returning base (i.e. scalar) data types.
+ */
+ TupleTableSlot *slot;
+
+ /*
+ * OPTIONAL pointer to misc user provided context info
+ *
+ * user_fctx is for use as a pointer to your own struct to retain
+ * arbitrary context information between calls for your function.
+ */
+ void *user_fctx;
+
+ /*
+ * OPTIONAL pointer to struct containing arrays of attribute type input
+ * metainfo
+ *
+ * attinmeta is for use when returning tuples (i.e. composite data types)
+ * and is not needed when returning base (i.e. scalar) data types. It
+ * is ONLY needed if you intend to use BuildTupleFromCStrings() to create
+ * the return tuple.
+ */
+ AttInMetadata *attinmeta;
+
+ /*
+ * memory context used for structures which must live for multiple calls
+ *
+ * multi_call_memory_ctx is set by SRF_FIRSTCALL_INIT() for you, and used
+ * by SRF_RETURN_DONE() for cleanup. It is the most appropriate memory
+ * context for any memory that is to be re-used across multiple calls
+ * of the SRF.
+ */
+ MemoryContext multi_call_memory_ctx;
+} FuncCallContext;
</programlisting>
- An SRF uses several functions and macros that automatically manipulate
- the FuncCallContext struct (and expect to find it via
- <literal>fn_extra</>). Use
+ An <acronym>SRF</> uses several functions and macros that
+ automatically manipulate the <structname>FuncCallContext</>
+ structure (and expect to find it via <literal>fn_extra</>). Use
<programlisting>
SRF_IS_FIRSTCALL()
</programlisting>
<programlisting>
SRF_FIRSTCALL_INIT()
</programlisting>
- to initialize the FuncCallContext struct. On every function call,
+ to initialize the <structname>FuncCallContext</>. On every function call,
including the first, use
<programlisting>
SRF_PERCALL_SETUP()
</programlisting>
- to properly set up for using the FuncCallContext struct and clearing
- any previously returned data left over from the previous pass.
+ to properly set up for using the <structname>FuncCallContext</>
+ and clearing any previously returned data left over from the
+ previous pass.
</para>
<para>
<programlisting>
SRF_RETURN_NEXT(funcctx, result)
</programlisting>
- to return it to the caller. (The <literal>result</>
- must be a Datum, either a single value or a tuple prepared as described
- earlier.) Finally, when your function is finished returning data, use
+ to return it to the caller. (The <literal>result</> must be a
+ <type>Datum</>, either a single value or a tuple prepared as
+ described earlier.) Finally, when your function is finished
+ returning data, use
<programlisting>
SRF_RETURN_DONE(funcctx)
</programlisting>
- to clean up and end the SRF.
+ to clean up and end the <acronym>SRF</>.
</para>
<para>
- The palloc memory context that is current when the SRF is called is
+ The memory context that is current when the <acronym>SRF</> is called is
a transient context that will be cleared between calls. This means
- that you do not need to be careful about pfree'ing everything
- you palloc; it will go away anyway. However, if you want to allocate
+ that you do not need to <function>pfree</> everything
+ you <function>palloc</>; it will go away anyway. However, if you want to allocate
any data structures to live across calls, you need to put them somewhere
else. The memory context referenced by
<structfield>multi_call_memory_ctx</> is a suitable location for any
- data that needs to survive until the SRF is finished running. In most
+ data that needs to survive until the <acronym>SRF</> is finished running. In most
cases, this means that you should switch into
<structfield>multi_call_memory_ctx</> while doing the first-call setup.
</para>
</para>
<para>
- A complete example of a simple SRF returning a composite type looks like:
+ A complete example of a simple <acronym>SRF</> returning a composite type looks like:
<programlisting>
PG_FUNCTION_INFO_V1(testpassbyval);
Datum
</para>
<para>
- See contrib/tablefunc for more examples of Table Functions.
+ See <filename>contrib/tablefunc</> for more examples of table functions.
</para>
</sect3>
programming language functions. Be warned: this section
of the manual will not make you a programmer. You must
have a good understanding of <acronym>C</acronym>
- (including the use of pointers and the malloc memory manager)
+ (including the use of pointers)
before trying to write <acronym>C</acronym> functions for
use with <productname>PostgreSQL</productname>. While it may
be possible to load functions written in languages other
<para>
The call handler is called in the same way as any other function:
It receives a pointer to a
- <structname>FunctionCallInfoData</structname> struct containing
+ <structname>FunctionCallInfoData</structname> <type>struct</> containing
argument values and information about the called function, and it
is expected to return a <type>Datum</type> result (and possibly
set the <structfield>isnull</structfield> field of the
- <structname>FunctionCallInfoData</structname> struct, if it wishes
+ <structname>FunctionCallInfoData</structname> structure, if it wishes
to return an SQL NULL result). The difference between a call
handler and an ordinary callee function is that the
<structfield>flinfo->fn_oid</structfield> field of the
- <structname>FunctionCallInfoData</structname> struct will contain
+ <structname>FunctionCallInfoData</structname> structure will contain
the OID of the actual function to be called, not of the call
handler itself. The call handler must use this field to determine
which function to execute. Also, the passed argument list has
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+$Header: /cvsroot/pgsql/doc/src/sgml/xindex.sgml,v 1.29 2002/09/21 18:32:54 petere Exp $
PostgreSQL documentation
-->
over a new type, nor associate operators of a new type with secondary
indexes.
To do these things, we must define an <firstterm>operator class</>
- for the new datatype. We will describe operator classes in the
+ for the new data type. We will describe operator classes in the
context of a running example: a new operator
class for the B-tree access method that stores and
sorts complex numbers in ascending absolute value order.
<note>
<para>
Prior to <productname>PostgreSQL</productname> release 7.3, it was
- necesssary to make manual additions to
+ necessary to make manual additions to
<classname>pg_amop</>, <classname>pg_amproc</>, and
<classname>pg_opclass</> in order to create a user-defined
operator class. That approach is now deprecated in favor of
access method needs to be able to use to work with a particular data type.
Operator classes are so called because one thing they specify is the set
of WHERE-clause operators that can be used with an index (ie, can be
- converted into an indexscan qualification). An operator class may also
+ converted into an index scan qualification). An operator class may also
specify some <firstterm>support procedures</> that are needed by the
internal operations of the index access method, but do not directly
correspond to any WHERE-clause operator that can be used with the index.
<para>
It is possible to define multiple operator classes for the same
- input datatype and index access method. By doing this, multiple
- sets of indexing semantics can be defined for a single datatype.
+ input data type and index access method. By doing this, multiple
+ sets of indexing semantics can be defined for a single data type.
For example, a B-tree index requires a sort ordering to be defined
- for each datatype it works on.
- It might be useful for a complex-number datatype
+ for each data type it works on.
+ It might be useful for a complex-number data type
to have one B-tree operator class that sorts the data by complex
absolute value, another that sorts by real part, and so on.
Typically one of the operator classes will be deemed most commonly
useful and will be marked as the default operator class for that
- datatype and index access method.
+ data type and index access method.
</para>
<para>
comparison it is. Instead, the index access method defines a set of
<quote>strategies</>, which can be thought of as generalized operators.
Each operator class shows which actual operator corresponds to each
- strategy for a particular datatype and interpretation of the index
+ strategy for a particular data type and interpretation of the index
semantics.
</para>
<para>
In short, an operator class must specify a set of operators that express
- each of these semantic ideas for the operator class's datatype.
+ each of these semantic ideas for the operator class's data type.
</para>
</sect1>
<para>
Just as with operators, the operator class identifies which specific
- functions should play each of these roles for a given datatype and
+ functions should play each of these roles for a given data type and
semantic interpretation. The index access method specifies the set
of functions it needs, and the operator class identifies the correct
functions to use by assigning <quote>support function numbers</> to them.
<programlisting>
OPERATOR 1 < (complex, complex) ,
</programlisting>
- but there is no need to do so when the operators take the same datatype
+ but there is no need to do so when the operators take the same data type
we are defining the operator class for.
</para>
</programlisting>
At present, only the GiST access method supports a
- <literal>STORAGE</> type that's different from the column datatype.
+ <literal>STORAGE</> type that's different from the column data type.
The GiST <literal>compress</> and <literal>decompress</> support
- routines must deal with datatype conversion when <literal>STORAGE</>
+ routines must deal with data-type conversion when <literal>STORAGE</>
is used.
</para>
</sect1>
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-$Header: /cvsroot/pgsql/doc/src/sgml/xoper.sgml,v 1.19 2002/05/11 02:09:41 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/xoper.sgml,v 1.20 2002/09/21 18:32:54 petere Exp $
-->
<Chapter Id="xoper">
<para>
Providing a negator is very helpful to the query optimizer since
- it allows expressions like NOT (x = y) to be simplified into
+ it allows expressions like <literal>NOT (x = y)</> to be simplified into
x <> y. This comes up more often than you might think, because
- NOTs can be inserted as a consequence of other rearrangements.
+ <literal>NOT</> operations can be inserted as a consequence of other rearrangements.
</para>
<para>
</sect2>
<sect2>
- <title>MERGES (SORT1, SORT2, LTCMP, GTCMP)</title>
+ <title><literal>MERGES</> (<literal>SORT1</>, <literal>SORT2</>, <literal>LTCMP</>, <literal>GTCMP</>)</title>
<para>
The <literal>MERGES</literal> clause, if present, tells the system that
it is permissible to use the merge join method for a join based on this
operator. <literal>MERGES</> only makes sense for binary operators that
return <literal>boolean</>, and in practice the operator must represent
- equality for some datatype or pair of datatypes.
+ equality for some data type or pair of data types.
</para>
<para>
it is possible to merge-join two
distinct data types so long as they are logically compatible. For
example, the <type>int2</type>-versus-<type>int4</type> equality operator
- is mergejoinable.
+ is merge-joinable.
We only need sorting operators that will bring both data types into a
logically compatible sequence.
</para>
<para>
Execution of a merge join requires that the system be able to identify
- four operators related to the mergejoin equality operator: less-than
- comparison for the left input datatype, less-than comparison for the
- right input datatype, less-than comparison between the two datatypes, and
- greater-than comparison between the two datatypes. (These are actually
- four distinct operators if the mergejoinable operator has two different
- input datatypes; but when the input types are the same the three
+ four operators related to the merge-join equality operator: less-than
+ comparison for the left input data type, less-than comparison for the
+ right input data type, less-than comparison between the two data types, and
+ greater-than comparison between the two data types. (These are actually
+ four distinct operators if the merge-joinable operator has two different
+ input data types; but when the input types are the same the three
less-than operators are all the same operator.)
It is possible to
specify these operators individually by name, as the <literal>SORT1</>,
</para>
<para>
- The input datatypes of the four comparison operators can be deduced
- from the input types of the mergejoinable operator, so just as with
+ The input data types of the four comparison operators can be deduced
+ from the input types of the merge-joinable operator, so just as with
<literal>COMMUTATOR</>, only the operator names need be given in these
clauses. Unless you are using peculiar choices of operator names,
it's sufficient to write <literal>MERGES</> and let the system fill in
<para>
There are additional restrictions on operators that you mark
- mergejoinable. These restrictions are not currently checked by
+ merge-joinable. These restrictions are not currently checked by
<command>CREATE OPERATOR</command>, but errors may occur when
the operator is used if any are not true:
<itemizedlist>
<listitem>
<para>
- A mergejoinable equality operator must have a mergejoinable
+ A merge-joinable equality operator must have a merge-joinable
commutator (itself if the two data types are the same, or a related
equality operator if they are different).
</para>
<listitem>
<para>
- If there is a mergejoinable operator relating any two data types
- A and B, and another mergejoinable operator relating B to any
- third data type C, then A and C must also have a mergejoinable
- operator; in other words, having a mergejoinable operator must
+ If there is a merge-joinable operator relating any two data types
+ A and B, and another merge-joinable operator relating B to any
+ third data type C, then A and C must also have a merge-joinable
+ operator; in other words, having a merge-joinable operator must
be transitive.
</para>
</listitem>
<para>
In <ProductName>PostgreSQL</ProductName> versions before 7.3,
the <literal>MERGES</> shorthand was not available: to make a
- mergejoinable operator one had to write both <literal>SORT1</> and
+ merge-joinable operator one had to write both <literal>SORT1</> and
<literal>SORT2</> explicitly. Also, the <literal>LTCMP</> and
<literal>GTCMP</>
options did not exist; the names of those operators were hardwired as
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/xplang.sgml,v 1.18 2002/08/22 00:01:40 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/xplang.sgml,v 1.19 2002/09/21 18:32:54 petere Exp $
-->
<chapter id="xplang">
In a default <productname>PostgreSQL</productname> installation,
the handler for the <application>PL/pgSQL</application> language
is built and installed into the <quote>library</quote>
- directory. If Tcl/Tk support is configured in, the handlers for
- PL/Tcl and PL/TclU are also built and installed in the same
- location. Likewise, the PL/Perl and PL/PerlU handlers are built
- and installed if Perl support is configured, and PL/Python is
+ directory. If <application>Tcl/Tk</> support is configured in, the handlers for
+ <application>PL/Tcl</> and <application>PL/TclU</> are also built and installed in the same
+ location. Likewise, the <application>PL/Perl</> and <application>PL/PerlU</> handlers are built
+ and installed if Perl support is configured, and <application>PL/Python</> is
installed if Python support is configured. The
<filename>createlang</filename> script automates <xref
linkend="xplang-install-cr1"> and <xref
projects / postgresql / commitdiff