<!--
-$PostgreSQL: pgsql/doc/src/sgml/ecpg.sgml,v 1.59 2003/12/26 20:00:00 meskes Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ecpg.sgml,v 1.60 2004/12/28 22:47:15 tgl Exp $
-->
<chapter id="ecpg">
</para>
<para>
- Admittedly, this documentation is quite incomplete. But since this
+ This documentation is quite incomplete. But since this
interface is standardized, additional information can be found in
many resources about SQL.
</para>
An embedded SQL program consists of code written in an ordinary
programming language, in this case C, mixed with SQL commands in
specially marked sections. To build the program, the source code
- is first passed to the embedded SQL preprocessor, which converts it
+ is first passed through the embedded SQL preprocessor, which converts it
to an ordinary C program, and afterwards it can be processed by a C
- compilation tool chain.
+ compiler.
</para>
<para>
</para>
<para>
- As indicated, programs written for the embedded
+ As already stated, programs written for the embedded
<acronym>SQL</acronym> interface are normal C programs with special
code inserted to perform database-related actions. This special
code always has the form
EXEC SQL ...;
</programlisting>
These statements syntactically take the place of a C statement.
- Depending on the particular statement, they may appear in the
- global context or within a function. Embedded
+ Depending on the particular statement, they may appear at the
+ global level or within a function. Embedded
<acronym>SQL</acronym> statements follow the case-sensitivity rules
of normal <acronym>SQL</acronym> code, and not those of C.
</para>
<para>
In the default mode, statements are committed only when
<command>EXEC SQL COMMIT</command> is issued. The embedded SQL
- interface also supports autocommit of transactions (as known from
- other interfaces) via the <option>-t</option> command-line option
- to <command>ecpg</command> (see below) or via the <literal>EXEC SQL
+ interface also supports autocommit of transactions (similar to
+ <application>libpq</> behavior) via the <option>-t</option> command-line
+ option to <command>ecpg</command> (see below) or via the <literal>EXEC SQL
SET AUTOCOMMIT TO ON</literal> statement. In autocommit mode, each
command is automatically committed unless it is inside an explicit
transaction block. This mode can be explicitly turned off using
<para>
The declarations are also echoed to the output file as a normal C
variables, so there's no need to declare them again. Variables
- that are not intended to be used with SQL commands can be declared
+ that are not intended to be used in SQL commands can be declared
normally outside these special sections.
</para>
second host variable specification to each host variable that
contains data. This second host variable is called the
<firstterm>indicator</firstterm> and contains a flag that tells
- whether the datums is null, in which case the value of the real
+ whether the datum is null, in which case the value of the real
host variable is ignored. Here is an example that handles the
retrieval of null values correctly:
<programlisting>
<title>sqlca</title>
<para>
- For a more powerful error handling, the embedded SQL interface
+ For more powerful error handling, the embedded SQL interface
provides a global variable with the name <varname>sqlca</varname>
that has the following structure:
<programlisting>
} sqlca;
</programlisting>
(In a multithreaded program, every thread automatically gets its
- own copy of <varname>sqlca</varname>. This works similar to the
+ own copy of <varname>sqlca</varname>. This works similarly to the
handling of the standard C global variable
<varname>errno</varname>.)
</para>
<para>
The structure <varname>sqlca</varname> is not defined in the SQL
standard, but is implemented in several other SQL database
- systems. The definitions are similar in the core, but if you want
+ systems. The definitions are similar at the core, but if you want
to write portable applications, then you should investigate the
different implementations carefully.
</para>
<programlisting>
cc -c prog1.c
</programlisting>
- The generated C source files include headers files from the
+ The generated C source files include header files from the
<productname>PostgreSQL</> installation, so if you installed
<productname>PostgreSQL</> in a location that is not searched by
default, you have to add an option such as
</para>
<para>
- <application>ecpg</application> is thread-safe if it is compiled using
- the <option>--enable-thread-safety</> <filename>configure</filename>
- command-line option. (You might need to use other threading
+ The <application>ecpg</application> library is thread-safe if it is built
+ using the <option>--enable-thread-safety</> command-line option to
+ <filename>configure</filename>. (You might need to use other threading
command-line options to compile your client code.)
</para>
</sect1>
<title>Internals</title>
<para>
- This section explain how <application>ECPG</application> works
+ This section explain
s how <application>ECPG</application> works
internally. This information can occasionally be useful to help
users understand how to use <application>ECPG</application>.
</para>
<!--
-$PostgreSQL: pgsql/doc/src/sgml/external-projects.sgml,v 1.5 2004/12/13 18:05:08 petere Exp $
+$PostgreSQL: pgsql/doc/src/sgml/external-projects.sgml,v 1.6 2004/12/28 22:47:15 tgl Exp $
-->
<chapter id="external-projects">
<productname>PostgreSQL</productname> is a complex software project,
and managing it is difficult. We have found that many
enhancements to <productname>PostgreSQL</productname> can be more
- efficiently developed independently of the main project. They can
- have their own developer teams, email lists, their own bug tracking,
- and their own release schedule. While their independence makes
- development easier, it makes user's jobs harder. They have to hunt
+ efficiently developed separately from the core project. Separate
+ projects can
+ have their own developer teams, email lists, bug tracking,
+ and release schedules. While their independence makes
+ development easier, it makes users' jobs harder. They have to hunt
around looking for database enhancements to meet their needs.
- This section outlines some of the more popular externally
+ This section describes some of the more popular externally
developed enhancements and guides you on how to find them.
</para>
+ <para>
+ Many <productname>PostgreSQL</productname>-related projects are
+ hosted at either
+ <productname>GBorg</> at <ulink url="http://gborg.postgresql.org">
+ http://gborg.postgresql.org</ulink> or
+ <productname>pgFoundry</> at <ulink
+ url="http://pgfoundry.org">http://pgfoundry.org</ulink>.
+ There are other
+ <productname>PostgreSQL</productname>-related projects that are hosted
+ elsewhere, but you will have to do an Internet search to find them.
+ </para>
+
<sect1 id="interfaces">
<title>Externally Developed Interfaces</title>
</para>
<para>
- To use other interfaces, you have to do some searching. For example,
- <productname>GBorg</> at <ulink url="http://gborg.postgresql.org">
- http://gborg.postgresql.org</ulink> has over thirty interfaces listed
- in its <literal>Drivers/Interfaces</> section. Some of the more
- popular interfaces are:
+ Some of the more popular interfaces are:
<variablelist>
<varlistentry>
</varlistentry>
<varlistentry>
- <term>Npgsql</term>
+ <term>pgjdbc</term>
<listitem>
<para>
- <application>.Net</> interface for more recent
- <application>Windows</> applications.
+ A <application>JDBC</> interface.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>libpq++</term>
+ <term>Npgsql</term>
<listitem>
<para>
- An older <application>C++</> interface.
+ <application>.Net</> interface for more recent
+ <application>Windows</> applications.
</para>
</listitem>
</varlistentry>
</varlistentry>
<varlistentry>
- <term>pgperl</term>
+ <term>libpq++</term>
<listitem>
<para>
- A <application>Perl</> interface with an <acronym>API</> similar
- to <application>libpq</>.
+ An older <application>C++</> interface.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>DBD-Pg</term>
+ <term>pgperl</term>
<listitem>
<para>
- A <application>Perl</> interface that uses the
- <acronym>DBD</>-standard <application>API</>.
+ A <application>Perl</> interface with an <acronym>API</> similar
+ to <application>libpq</>.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>pgtcl</term>
+ <term>DBD-Pg</term>
<listitem>
<para>
- The original version of the <application>TCL</> interface.
+ A <application>Perl</> interface that uses the
+ <acronym>DBD</>-standard <application>API</>.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>PyGreSQL</term>
+ <term>pgtclng</term>
<listitem>
<para>
- A <application>Python</> interface library.
+ A newer version of the <application>Tcl</> interface.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>pgjdbc</term>
+ <term>pgtcl</term>
<listitem>
<para>
- A <application>JDBC</> interface.
+ The original version of the <application>Tcl</> interface.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>pgtclng</term>
+ <term>PyGreSQL</term>
<listitem>
<para>
- A newer version of the <application>TCL</> interface.
+ A <application>Python</> interface library.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
- <para>
- That section also contains several server-side languages that are
- separate projects. <application>pgFoundry</> at <ulink
- url="http://pgfoundry.org">http://pgfoundry.org</ulink> contains
- even more projects. Other projects are not even hosted on these
- servers and you will have to do an Internet search to find them.
- </para>
-
</sect1>
<sect1 id="extensions">
like <application>PostGIS</>. Even <application>PostgreSQL</>
replication solutions are developed externally. For example,
<application>Slony-I</> is a popular master/slave replication solution
- that is developed independently from the main projects.
+ that is developed independently from the core project.
</para>
<para>
-<!-- $PostgreSQL: pgsql/doc/src/sgml/information_schema.sgml,v 1.19 2004/11/27 21:27:06 petere Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/information_schema.sgml,v 1.20 2004/12/28 22:47:15 tgl Exp $ -->
<chapter id="information-schema">
<title>The Information Schema</title>
exists in all databases. The owner of this schema is the initial
database user in the cluster, and that user naturally has all the
privileges on this schema, including the ability to drop it (but
- the space savings achieved by this are minuscule).
+ the space savings achieved by that are minuscule).
</para>
<para>
function (as parameter or return type) and stores some information
about how the data type is used in that instance (for example, the
declared maximum length, if applicable). Each data type
- descriptors is assigned an arbitrary identifier that is unique
+ descriptor is assigned an arbitrary identifier that is unique
among the data type descriptor identifiers assigned for one object
(table, domain, function). This view is probably not useful for
applications, but it is used to define some other views in the
in the current database that are restricted by some unique, primary
key, or foreign key constraint. Check constraints are not included
in this view. Only those columns are shown that are contained in a
- table owned the current user.
+ table owned by the current user.
</para>
<table>
<para>
The table <literal>sql_packages</literal> contains information
- about which features packages defined in the SQL standard are
+ about which feature packages defined in the SQL standard are
supported by <productname>PostgreSQL</productname>. Refer to <xref
linkend="features"> for background information on feature packages.
</para>
incompatibilities with the SQL standard that affect the
representation in the information schema. First, trigger names are
local to the table in <productname>PostgreSQL</productname>, rather
- than independent schema objects. Therefore there may be duplicate
+ than being independent schema objects. Therefore there may be duplicate
trigger names defined in one schema, as long as they belong to
different tables. (<literal>trigger_catalog</literal> and
<literal>trigger_schema</literal> are really the values pertaining
<!--
-$PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.172 2004/12/20 18:15:05 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.173 2004/12/28 22:47:15 tgl Exp $
-->
<chapter id="libpq">
<application>libpq</> is a set of library functions that allow
client programs to pass queries to the <productname>PostgreSQL</>
backend server and to receive the results of these queries.
+ </para>
+
+ <para>
<application>libpq</> is also the underlying engine for several
other <productname>PostgreSQL</> application interfaces, including
- those written for C++,
TCL, Perl, Python and <application>ECPG</>.
+ those written for C++,
Perl, Python, Tcl and <application>ECPG</>.
So some aspects of <application>libpq</>'s behavior will be
- important to you if you use one of those packages.
+ important to you if you use one of those packages. In particular,
+ <xref linkend="libpq-envars">,
+ <xref linkend="libpq-pgpass"> and
+ <xref linkend="libpq-ssl">
+ describe behavior that is visible to the user of any application
+ that uses <application>libpq</>.
</para>
<para>
application program can have several backend connections open at
one time. (One reason to do that is to access more than one
database.) Each connection is represented by a
- <structname>PGconn</><indexterm><primary>PGconn</></> object which
+ <structname>PGconn</><indexterm><primary>PGconn</></> object, which
is obtained from the function <function>PQconnectdb</> or
<function>PQsetdbLogin</>. Note that these functions will always
return a non-null object pointer, unless perhaps there is too
can be empty to use all default parameters, or it can contain one or more
parameter settings separated by whitespace.
Each parameter setting is in the form <literal>keyword = value</literal>.
- (To write an empty value or a value containing
+ Spaces around the equal sign are optional.
+ To write an empty value or a value containing
spaces, surround it with single quotes, e.g.,
<literal>keyword = 'a value'</literal>.
Single quotes and backslashes within the value must be escaped with a
- backslash, i.e., <literal>\'</literal> and <literal>\\</literal>.)
- Spaces around the equal sign are optional.
+ backslash, i.e., <literal>\'</literal> and <literal>\\</literal>.
</para>
<para>
<listitem>
<para>
<productname>PostgreSQL</productname> user name to connect as.
+ Defaults to be the same as the operating system name of the user
+ running the application.
</para>
</listitem>
</varlistentry>
If <productname>PostgreSQL</> is compiled without SSL support,
using option <literal>require</> will cause an error, while
options <literal>allow</> and <literal>prefer</> will be
- tolerated but <application>libpq</> will be unable to negotiate
+ accepted but <application>libpq</> will not in fact attempt
an <acronym>SSL</>
connection.<indexterm><primary>SSL</><secondary
sortas="libpq">with libpq</></indexterm>
name in <filename>pg_service.conf</filename> that holds additional connection parameters.
This allows applications to specify only a service name so connection parameters
can be centrally maintained. See
- <filename><replaceable>PREFIX</>/share/pg_service.conf.sample</> for
- information on how to set up the file.
+ <filename>share/pg_service.conf.sample</> in the installation
+ directory for information on how to set up the file.
</para>
</listitem>
</varlistentry>
If any parameter is unspecified, then the corresponding
environment variable (see <xref linkend="libpq-envars">)
is checked. If the environment variable is not set either,
- then built-in defaults are used.
+ then the indicated built-in defaults are used.
</para>
</listitem>
</varlistentry>
</variablelist>
Note that, although these constants will remain (in order to maintain
- compatibility), an application should never rely upon these appearing in a
+ compatibility), an application should never rely upon these occurring in a
particular order, or at all, or on the status always being one of these
documented values. An application might do something like this:
<programlisting>
<application>libpq</> includes logic to obtain values for
<literal>server_version</> and <literal>client_encoding</> anyway.
Applications are encouraged to use <function>PQparameterStatus</>
-rather than ad-hoc code to determine these values. (Beware however
+rather than <foreignphrase>ad hoc</> code to determine these values.
+(Beware however
that on a pre-3.0 connection, changing <literal>client_encoding</> via
<command>SET</> after connection startup will not be reflected by
<function>PQparameterStatus</>.) For <literal>server_version</>,
are supported.
Currently, the possible values are 2 (2.0 protocol), 3 (3.0 protocol),
or zero (connection bad). This will not change after connection
-startup is complete, but it could theoretically change during a reset.
-The 3.0 protocol will normally be used when communicating with
+startup is complete, but it could theoretically change during a connection
+reset. The 3.0 protocol will normally be used when communicating with
<productname>PostgreSQL</> 7.4 or later servers; pre-7.4 servers support
only protocol 2.0. (Protocol 1.0 is obsolete and not supported by <application>libpq</application>.)
</para>
<function>PQerrorMessage</function> result will
include a trailing newline. The caller should not free the result
directly. It will be freed when the associated <structname>PGconn</>
- handle is passed to <function>PQfinish</function>.
+ handle is passed to <function>PQfinish</function>. The result string
+ should not be expected to remain the same across operations on the
+ <literal>PGconn</> structure.
</para>
</listitem>
</varlistentry>
</para>
<para>
You must define <symbol>USE_SSL</symbol> in order to get the
- prototype for this function. Doing this will also
+ correct prototype for this function. Doing this will also
automatically include <filename>ssl.h</filename> from <productname>OpenSSL</productname>.
</para>
</listitem>
<para>
Returns the column number (within its table) of the column making up
the specified query result column.
- Result column numbers start at 0.
+ Query-result column numbers start at 0, but table columns have nonzero
+ numbers.
<synopsis>
int PQftablecol(const PGresult *res,
int column_number);
<listitem>
<para>
Creates a data structure containing the information needed to cancel
- a command issued through a particular database connection.
+ a command issued through a particular database connection.
<synopsis>
PGcancel *PQgetCancel(PGconn *conn);
</synopsis>
</indexterm>
<envar>PGHOST</envar> sets the database server name.
If this begins with a slash, it specifies Unix-domain communication
-rather than TCP/IP communication; the value is the name of the
-directory in which the socket file is stored (default <filename>/tmp</filename>).
+rather than TCP/IP communication; the value is then the name of the
+directory in which the socket file is stored (in a default installation
+setup this would be <filename>/tmp</filename>).
</para>
</listitem>
<listitem>
<primary><envar>PGHOSTADDR</envar></primary>
</indexterm>
<envar>PGHOSTADDR</envar> specifies the numeric IP address of the database
-server. This can be set instead of <envar>PGHOST</envar> to avoid DNS
-lookup overhead. See the documentation of
+server. This can be set instead of or in addition to <envar>PGHOST</envar>
+to avoid DNS lookup overhead. See the documentation of
these parameters, under <function>PQconnectdb</function> above, for details
on their interaction.
</para>
<envar>PGPASSWORD</envar>
sets the password used if the server demands password
authentication. This environment variable is deprecated for security
-reasons; consider migrating to use the <filename>$HOME/.pgpass</>
+reasons; instead consider using the <filename>$HOME/.pgpass</>
file (see <xref linkend="libpq-pgpass">).
</para>
</listitem>
connection, then if that fails, trying a regular non-<acronym>SSL</>
connection; <literal>require</> will try only an <acronym>SSL</>
connection. If <productname>PostgreSQL</> is compiled without SSL support,
-using option <literal>require</> will cause an error, and options
-<literal>allow</> and <literal>prefer</> will be tolerated but
-<application>libpq</> will
be unable to negotiate an <acronym>SSL</>
+using option <literal>require</> will cause an error, while options
+<literal>allow</> and <literal>prefer</> will be accepted but
+<application>libpq</> will
not in fact attempt an <acronym>SSL</>
connection.
</para>
</listitem>
<para>
The following environment variables can be used to specify default
behavior for each <productname>PostgreSQL</productname> session.
-(See also the <command>ALTER USER</> and <command>ALTER DATABASE</>
+(See also the
+<xref linkend="sql-alteruser" endterm="sql-alteruser-title"> and
+<xref linkend="sql-alterdatabase" endterm="sql-alterdatabase-title">
commands for ways to set default behavior on a per-user or per-database
basis.)
(Equivalent to <literal>SET geqo TO ...</literal>.)
</para>
</listitem>
+</itemizedlist>
+
+Refer to the <acronym>SQL</acronym> command
+<xref linkend="sql-set" endterm="sql-set-title">
+for information on correct values for these environment variables.
+</para>
+
+<para>
+The following environment variables determine internal behavior of
+<application>libpq</application>; they override compiled-in defaults.
+
+<itemizedlist>
<listitem>
<para>
<indexterm>
<primary><envar>PGLOCALEDIR</envar></primary>
</indexterm>
<envar>PGLOCALEDIR</envar>
-sets the directory containing the <literal>locale</> files.
+sets the directory containing the <literal>locale</> files for message
+internationalization.
</para>
</listitem>
</itemizedlist>
-
-Refer to the <acronym>SQL</acronym> command <command>SET</command>
-for information on correct values for these environment variables.
</para>
</sect1>
<para>
<application>libpq</application> is reentrant and thread-safe if the
<filename>configure</filename> command-line option
-<literal>--enable-thread-safety</> has been used when the
+<literal>--enable-thread-safety</> was used when the
<productname>PostgreSQL</productname> distribution was built. In
addition, you might need to use additional compiler command-line
options when you compile your application code. Refer to your
</indexterm>
<para>
- To build (i.e., compile and link) your <application>libpq</application> programs you need to
+ To build (i.e., compile and link) a program using
+ <application>libpq</application> you need to
do all of the following things:
<itemizedlist>
<!--
-$PostgreSQL: pgsql/doc/src/sgml/lobj.sgml,v 1.33 2003/11/29 19:51:37 pgsql Exp $
+$PostgreSQL: pgsql/doc/src/sgml/lobj.sgml,v 1.34 2004/12/28 22:47:15 tgl Exp $
-->
<chapter id="largeObjects">
<indexterm><primary>BLOB</><see>large object</></>
<para>
- In <productname>PostgreSQL</productname> releases prior to 7.1,
- the size of any row in the database could not exceed the size of a
- data page. Since the size of a data page is 8192 bytes (the
- default, which can be raised up to 32768), the upper limit on the
- size of a data value was relatively low. To support the storage of
- larger atomic values, <productname>PostgreSQL</productname>
- provided and continues to provide a large object interface. This
- interface provides file-oriented access to user data that is stored in
- a special large-object structure.
+ <productname>PostgreSQL</productname> has a <firstterm>large object</>
+ facility, which provides stream-style access to user data that is stored
+ in a special large-object structure. Streaming access is useful
+ when working with data values that are too large to manipulate
+ conveniently as a whole.
</para>
<para>
<indexterm><primary>sliced bread</><see>TOAST</></indexterm>
<productname>PostgreSQL 7.1</productname> introduced a mechanism
(nicknamed <quote><acronym>TOAST</acronym></quote>) that allows
- data rows to be much larger than individual data pages. This
- makes the large object interface partially obsolete. One
- remaining advantage of the large object interface is that it allows values up
- to 2 GB in size, whereas <acronym>TOAST</acronym> can only handle 1 GB.
+ data values to be much larger than single pages. This
+ makes the large object facility partially obsolete. One
+ remaining advantage of the large object facility is that it allows values
+ up to 2 GB in size, whereas <acronym>TOAST</acronym>ed fields can be at
+ most 1 GB. Also, large objects can be manipulated piece-by-piece much more
+ easily than ordinary data fields, so the practical limits are considerably
+ different.
</para>
</sect1>
creates a new large object.
<replaceable class="parameter">mode</replaceable> is a bit mask
describing several different attributes of the new
- object. The symbolic constants listed here are defined
+ object. The symbolic constants used here are defined
in the header file <filename>libpq/libpq-fs.h</filename>.
The access type (read, write, or both) is controlled by
or'ing together the bits <symbol>INV_READ</symbol> and
specifies the operating system name of
the file to be imported as a large object.
The return value is the OID that was assigned to the new large object.
+ Note that the file is read by the client interface library, not by
+ the server; so it must exist in the client filesystem and be readable
+ by the client application.
</para>
</sect2>
<indexterm><primary>lo_export</></>
The <parameter>lobjId</parameter> argument specifies the OID of the large
object to export and the <parameter>filename</parameter> argument specifies
- the operating system name name of the file.
+ the operating system name of the file.
+ Note that the file is written by the client interface library, not by
+ the server.
</para>
</sect2>
</synopsis>
<indexterm><primary>lo_write</></> writes
<parameter>len</parameter> bytes from <parameter>buf</parameter>
- to large object <parameter>fd</>. The <parameter>fd</parameter>
+ to large object
descriptor <parameter>fd</>. The <parameter>fd</parameter>
argument must have been returned by a previous
<function>lo_open</function>. The number of bytes actually
written is returned. In the event of an error, the return value
int lo_read(PGconn *conn, int fd, char *buf, size_t len);
</synopsis>
<indexterm><primary>lo_read</></> reads
- <parameter>len</parameter> bytes from large object
+ <parameter>len</parameter> bytes from large object descriptor
<parameter>fd</parameter> into <parameter>buf</parameter>. The
<parameter>fd</parameter> argument must have been returned by a
previous <function>lo_open</function>. The number of bytes
</sect2>
<sect2>
-<title>Seeking on a Large Object</title>
+<title>Seeking in a Large Object</title>
<para>
- To change the current read or write location on a large
- object, call
+ To change the current read or write location associated with a
+ large object descriptor, call
<synopsis>
int lo_lseek(PGconn *conn, int fd, int offset, int whence);
</synopsis>
<indexterm><primary>lo_lseek</></> This function moves the
- current location pointer for the large object described by
+ current location pointer for the large object descriptor identified by
<parameter>fd</> to the new location specified by
<parameter>offset</>. The valid values for <parameter>whence</>
are <symbol>SEEK_SET</> (seek from object start),
<title>Obtaining the Seek Position of a Large Object</title>
<para>
- To obtain the current read or write location of a large object,
+ To obtain the current read or write location of a large object descriptor,
call
<synopsis>
int lo_tell(PGconn *conn, int fd);
<title>Closing a Large Object Descriptor</title>
<para>
- A large object may be closed by calling
+ A large object descriptor may be closed by calling
<synopsis>
int lo_close(PGconn *conn, int fd);
</synopsis>
projects / postgresql / commitdiff