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+$Header: /cvsroot/pgsql/doc/src/sgml/ref/abort.sgml,v 1.12 2003/04/15 13:25:08 petere Exp $
PostgreSQL documentation
-->
<refentrytitle id="sql-abort-title">ABORT</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
+
<refnamediv>
- <refname>
- ABORT
- </refname>
- <refpurpose>
- abort the current transaction
- </refpurpose>
+ <refname>ABORT</refname>
+ <refpurpose>abort the current transaction</refpurpose>
</refnamediv>
+
<refsynopsisdiv>
- <refsynopsisdivinfo>
- <date>1999-07-20</date>
- </refsynopsisdivinfo>
- <synopsis>
+<synopsis>
ABORT [ WORK | TRANSACTION ]
- </synopsis>
-
- <refsect2 id="R2-SQL-ABORT-1">
- <refsect2info>
- <date>1998-09-27</date>
- </refsect2info>
- <title>
- Inputs
- </title>
-
- <para>
- None.
- </para>
- </refsect2>
-
- <refsect2 id="R2-SQL-ABORT-2">
- <refsect2info>
- <date>1998-09-27</date>
- </refsect2info>
- <title>
- Outputs
- </title>
-
- <para>
-
- <variablelist>
- <varlistentry>
- <term><computeroutput>
-ROLLBACK
- </computeroutput></term>
- <listitem>
- <para>
- Message returned if successful.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><computeroutput>
-WARNING: ROLLBACK: no transaction in progress
- </computeroutput></term>
- <listitem>
- <para>
- If there is not any transaction currently in progress.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
- </refsect2>
+</synopsis>
</refsynopsisdiv>
- <refsect1 id="R1-SQL-ABORT-1">
- <refsect1info>
- <date>1998-09-27</date>
- </refsect1info>
- <title>
- Description
- </title>
+ <refsect1>
+ <title>Description</title>
+
<para>
<command>ABORT</command> rolls back the current transaction and causes
all the updates made by the transaction to be discarded.
This command is identical
- in behavior to the <acronym>SQL92</acronym> command <command>ROLLBACK</command>,
+ in behavior to the standard <acronym>SQL</acronym> command <command>ROLLBACK</command>,
and is present only for historical reasons.
</para>
- <refsect2 id="R2-SQL-ABORT-3">
- <refsect2info>
- <date>1998-09-27</date>
- </refsect2info>
- <title>
- Notes
- </title>
- <para>
- Use <command>COMMIT</command> to successfully
- terminate a transaction.
- </para>
- </refsect2>
</refsect1>
- <refsect1 id="R1-SQL-ABORT-2">
- <title>
- Usage
- </title>
+ <refsect1>
+ <title>Diagnostics</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><computeroutput>ROLLBACK</computeroutput></term>
+ <listitem>
+ <para>
+ Message returned if successful.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><computeroutput>WARNING: ROLLBACK: no transaction in progress</computeroutput></term>
+ <listitem>
+ <para>
+ If there is not any transaction currently in progress.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Notes</title>
+
+ <para>
+ Use <command>COMMIT</command> to successfully
+ terminate a transaction.
+ </para>
+ </refsect1>
+
+ <refsect1>
+ <title>Examples</title>
+
<para>
To abort all changes:
+<programlisting>
ABORT WORK;
- </programlisting>
+</programlisting>
</para>
-
</refsect1>
- <refsect1 id="R1-SQL-ABORT-3">
- <title>
- Compatibility
- </title>
-
- <refsect2 id="R2-SQL-ABORT-4">
- <refsect2info>
- <date>1998-09-27</date>
- </refsect2info>
- <title>
- SQL92
- </title>
- <para>
- This command is a <productname>PostgreSQL</productname> extension present
- for historical reasons. <command>ROLLBACK</command> is the <acronym>SQL92</acronym>
- equivalent command.
- </para>
- </refsect2>
+ <refsect1>
+ <title>Compatibility</title>
+
+ <para>
+ This command is a <productname>PostgreSQL</productname> extension
+ present for historical reasons. <command>ROLLBACK</command> is the
+ equivalent standard SQL command.
+ </para>
</refsect1>
</refentry>
<!--
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PostgreSQL documentation
-->
value becomes the session default value.
The database-specific default
overrides whatever setting is present in <filename>postgresql.conf</>
- or has been received from the postmaster.
+ or has been received from the <command>postmaster</command> command line.
</para>
<para>
- Only a superuser or the database owner can change the session defaults for a
+ Only the database owner or a superuser can change the session defaults for a
database.
</para>
+ </refsect1>
- <refsect2>
- <title>Parameters</title>
+ <refsect1>
+ <title>Parameters</title>
- <para>
<variablelist>
<varlistentry>
<term><replaceable class="PARAMETER">name</replaceable></term>
</listitem>
</varlistentry>
</variablelist>
- </para>
- </refsect2>
</refsect1>
<refsect1>
<title>Diagnostics</title>
- <para>
<variablelist>
<varlistentry>
<term><computeroutput>ALTER DATABASE</computeroutput></term>
</listitem>
</varlistentry>
</variablelist>
- </para>
</refsect1>
<refsect1>
<!--
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PostgreSQL documentation
-->
<refentrytitle id="SQL-ALTERGROUP-title">ALTER GROUP</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
+
<refnamediv>
- <refname>
- ALTER GROUP
- </refname>
- <refpurpose>
- add users to a group or remove users from a group
- </refpurpose>
+ <refname>ALTER GROUP</refname>
+ <refpurpose>add users to a group or remove users from a group</refpurpose>
</refnamediv>
+
<refsynopsisdiv>
- <refsynopsisdivinfo>
- <date>2000-01-14</date>
- </refsynopsisdivinfo>
- <synopsis>
-ALTER GROUP <replaceable class="PARAMETER">name</replaceable> ADD USER <replaceable class="PARAMETER">username</replaceable> [, ... ]
-ALTER GROUP <replaceable class="PARAMETER">name</replaceable> DROP USER <replaceable class="PARAMETER">username</replaceable> [, ... ]
- </synopsis>
-
- <refsect2 id="R2-SQL-ALTERGROUP-1">
- <refsect2info>
- <date>2000-01-14</date>
- </refsect2info>
- <title>
- Inputs
- </title>
-
- <para>
- <variablelist>
- <varlistentry>
- <term><replaceable class="PARAMETER">name</replaceable></term>
- <listitem>
- <para>
- The name of the group to modify.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><replaceable class="PARAMETER">username</replaceable></term>
- <listitem>
- <para>
- Users which are to be added or removed from the group. The user
- names must exist.
- </para>
- </listitem>
- </varlistentry>
-
- </variablelist>
- </para>
- </refsect2>
-
- <refsect2 id="R2-SQL-ALTERGROUP-2">
- <refsect2info>
- <date>2000-01-14</date>
- </refsect2info>
- <title>
- Outputs
- </title>
- <para>
- <variablelist>
- <varlistentry>
- <term><computeroutput>ALTER GROUP</computeroutput></term>
- <listitem>
- <para>
- Message returned if the alteration was successful.
- </para>
- </listitem>
- </varlistentry>
-
- </variablelist>
- </para>
- </refsect2>
+<synopsis>
+ALTER GROUP <replaceable class="PARAMETER">groupname</replaceable> ADD USER <replaceable class="PARAMETER">username</replaceable> [, ... ]
+ALTER GROUP <replaceable class="PARAMETER">groupname</replaceable> DROP USER <replaceable class="PARAMETER">username</replaceable> [, ... ]
+</synopsis>
</refsynopsisdiv>
- <refsect1 id="R1-SQL-ALTERGROUP-1">
- <refsect1info>
- <date>2000-01-14</date>
- </refsect1info>
- <title>
- Description
- </title>
+ <refsect1>
+ <title>Description</title>
+
<para>
<command>ALTER GROUP</command> is used to add or remove users from a
group. Only database superusers can use this command.
Adding a user to a group does not create the user. Similarly, removing
a user from a group does not drop the user itself.
</para>
+
<para>
Use <xref linkend="SQL-CREATEGROUP" endterm="SQL-CREATEGROUP-title">
to create a new group and <xref linkend="SQL-DROPGROUP"
</para>
</refsect1>
- <refsect1 id="R1-SQL-ALTERGROUP-2">
- <title>
- Usage
- </title>
+ <refsect1>
+ <title>Parameter</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><replaceable class="PARAMETER">groupname</replaceable></term>
+ <listitem>
+ <para>
+ The name of the group to modify.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">username</replaceable></term>
+ <listitem>
+ <para>
+ Users which are to be added or removed from the group. The users
+ must exist.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Diagnostics</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><computeroutput>ALTER GROUP</computeroutput></term>
+ <listitem>
+ <para>
+ Message returned if the alteration was successful.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Examples</title>
<para>
Add users to a group:
</para>
</refsect1>
- <refsect1 id="R1-SQL-ALTERGROUP-3">
- <title>
- Compatibility
- </title>
+ <refsect1>
+ <title>Compatibility</title>
- <refsect2 id="R2-SQL-ALTERGROUP-4">
- <refsect2info>
- <date>2000-01-14</date>
- </refsect2info>
- <title>
- SQL92
- </title>
- <para>
- There is no <command>ALTER GROUP</command> statement in
- <acronym>SQL92</acronym>. The concept of roles is
- similar.
- </para>
- </refsect2>
+ <para>
+ There is no <command>ALTER GROUP</command> statement in the SQL
+ standard. The concept of roles is similar.
+ </para>
</refsect1>
</refentry>
<!--
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PostgreSQL documentation
-->
<refentrytitle id="sql-altertable-title">ALTER TABLE</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
+
<refnamediv>
- <refname>
- ALTER TABLE
- </refname>
- <refpurpose>
- change the definition of a table
- </refpurpose>
+ <refname>ALTER TABLE</refname>
+ <refpurpose>change the definition of a table</refpurpose>
</refnamediv>
+
<refsynopsisdiv>
- <refsynopsisdivinfo>
- <date>1999-07-20</date>
- </refsynopsisdivinfo>
- <synopsis>
+<synopsis>
ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
ADD [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> <replaceable class="PARAMETER">type</replaceable> [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ]
ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
CLUSTER ON <replaceable class="PARAMETER">index_name</replaceable>
- </synopsis>
-
- <refsect2 id="R2-SQL-ALTERTABLE-1">
- <refsect2info>
- <date>1998-04-15</date>
- </refsect2info>
- <title>
- Inputs
- </title>
- <para>
- <variablelist>
-
- <varlistentry>
- <term><replaceable class="PARAMETER"> table </replaceable></term>
- <listitem>
- <para>
- The name (possibly schema-qualified) of an existing table to
- alter. If <literal>ONLY</> is specified, only that table is
- altered. If <literal>ONLY</> is not specified, the table and all
- its descendant tables (if any) are updated. <literal>*</> can be
- appended to the table name to indicate that descendant tables are
- to be scanned, but in the current version, this is the default
- behavior. (In releases before 7.1, <literal>ONLY</> was the
- default behavior.) The default can be altered by changing the
- <option>SQL_INHERITANCE</option> configuration option.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><replaceable class="PARAMETER"> column </replaceable></term>
- <listitem>
- <para>
- Name of a new or existing column.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><replaceable class="PARAMETER"> type </replaceable></term>
- <listitem>
- <para>
- Type of the new column.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><replaceable class="PARAMETER"> new_column </replaceable></term>
- <listitem>
- <para>
- New name for an existing column.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><replaceable class="PARAMETER"> new_table </replaceable></term>
- <listitem>
- <para>
- New name for the table.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><replaceable class="PARAMETER"> table_constraint </replaceable></term>
- <listitem>
- <para>
- New table constraint for the table.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><replaceable class="PARAMETER"> constraint_name </replaceable></term>
- <listitem>
- <para>
- Name of an existing constraint to drop.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><replaceable class="PARAMETER">new_owner </replaceable></term>
- <listitem>
- <para>
- The user name of the new owner of the table.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><replaceable class="PARAMETER"> index_name </replaceable></term>
- <listitem>
- <para>
- The index name on which the table should be marked for clustering.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term>CASCADE</term>
- <listitem>
- <para>
- Automatically drop objects that depend on the dropped column
- or constraint (for example, views referencing the column).
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term>RESTRICT</term>
- <listitem>
- <para>
- Refuse to drop the column or constraint if there are any dependent
- objects. This is the default behavior.
- </para>
- </listitem>
- </varlistentry>
-
- </variablelist>
- </para>
- </refsect2>
-
- <refsect2 id="R2-SQL-ALTERTABLE-2">
- <refsect2info>
- <date>1998-04-15</date>
- </refsect2info>
- <title>
- Outputs
- </title>
- <para>
-
- <variablelist>
- <varlistentry>
- <term><computeroutput>ALTER TABLE</computeroutput></term>
- <listitem>
- <para>
- Message returned from column or table renaming.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><computeroutput>ERROR</computeroutput></term>
- <listitem>
- <para>
- Message returned if table or column is not available.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
- </refsect2>
+</synopsis>
</refsynopsisdiv>
- <refsect1 id="R1-SQL-ALTERTABLE-1">
- <refsect1info>
- <date>1998-04-15</date>
- </refsect1info>
- <title>
- Description
- </title>
+ <refsect1>
+ <title>Description</title>
+
<para>
<command>ALTER TABLE</command> changes the definition of an existing table.
- There are several sub-forms:
- </para>
+ There are several subforms:
<variablelist>
-
<varlistentry>
- <term>ADD COLUMN</term>
+ <term><literal>ADD COLUMN</literal></term>
<listitem>
<para>
This form adds a new column to the table using the same syntax as
</varlistentry>
<varlistentry>
- <term>DROP COLUMN</term>
+ <term><literal>DROP COLUMN</literal></term>
<listitem>
<para>
- This form drops a column from a table. Note that indexes and
+ This form drops a column from a table. Indexes and
table constraints involving the column will be automatically
dropped as well. You will need to say <literal>CASCADE</> if
- anything outside the table depends on the column --- for example,
- foreign key references, views, etc.
+ anything outside the table depends on the column, for example,
+ foreign key references or views.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>SET/DROP DEFAULT</term>
+ <term><literal>SET</literal>/<literal>DROP DEFAULT</literal></term>
<listitem>
<para>
- These forms set or remove the default value for a column. Note
- that defaults only apply to subsequent <command>INSERT</command>
+ These forms set or remove the default value for a column.
+ The default values only apply to subsequent <command>INSERT</command>
commands; they do not cause rows already in the table to change.
Defaults may also be created for views, in which case they are
inserted into <command>INSERT</> statements on the view before
- the view's ON INSERT rule is applied.
+ the view's <literal>ON INSERT</literal> rule is applied.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>SET/DROP NOT NULL</term>
+ <term><literal>SET</literal>/<literal>DROP NOT NULL</literal></term>
<listitem>
<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 null values in the column.
+ These forms change whether a column is marked to allow null
+ values or to reject null values. You can only use <literal>SET
+ NOT NULL</> when the column contains no null values.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>SET STATISTICS</term>
+ <term><literal>SET STATISTICS</literal></term>
<listitem>
<para>
This form
</varlistentry>
<varlistentry>
- <term>SET STORAGE</term>
+ <term><literal>SET STORAGE</literal></term>
<listitem>
<para>
This form sets the storage mode for a column. This controls whether this
column is held inline or in a supplementary table, and whether the data
should be compressed or not. <literal>PLAIN</literal> must be used
- for fixed-length values such as <literal>INTEGER</literal> and is
+ for fixed-length values such as <type>integer</type> and is
inline, uncompressed. <literal>MAIN</literal> is for inline,
compressible data. <literal>EXTERNAL</literal> is for external,
- uncompressed data and <literal>EXTENDED</literal> is for external,
+ uncompressed data, and <literal>EXTENDED</literal> is for external,
compressed data. <literal>EXTENDED</literal> is the default for all
- data types that support it. The use of <literal>EXTERNAL</literal> will
- make substring operations on a TEXT column faster, at the penalty of
+ data types that support it. The use of <literal>EXTERNAL</literal> will, for example,
+ make substring operations on a <type>text</type> column faster, at the penalty of
increased storage space.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>SET WITHOUT OIDS</term>
+ <term><literal>SET WITHOUT OIDS</literal></term>
<listitem>
<para>
- Removes the <literal>OID</literal> column from the the table. Removing (setting without)
- oids from a table also do not occur immediately. The space an <literal>OID</literal>
- uses will be reclaimed when the tuple is updated. Without updating the tuple, both the
- space and the value of the <literal>OID</literal> are maintained indefinitely. This is
- semantically similar to the <literal>DROP COLUMN</literal> process.
+ This form removes the <literal>oid</literal> column from the
+ table. Removing OIDs from a table does not occur immediately.
+ The space that the OID uses will be reclaimed when the row is
+ updated. Without updating the row, both the space and the value
+ of the OID are kept indefinitely. This is semantically similar
+ to the <literal>DROP COLUMN</literal> process.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>RENAME</term>
+ <term><literal>RENAME</literal></term>
<listitem>
<para>
The <literal>RENAME</literal> forms change the name of a table
</varlistentry>
<varlistentry>
- <term>ADD <replaceable class="PARAMETER">table_constraint</replaceable></term>
+ <term><literal>ADD <replaceable class="PARAMETER">table_constraint</replaceable></literal></term>
<listitem>
<para>
This form adds a new constraint to a table using the same syntax as
</varlistentry>
<varlistentry>
- <term>DROP CONSTRAINT</term>
+ <term><literal>DROP CONSTRAINT</literal></term>
<listitem>
<para>
This form drops constraints on a table.
</varlistentry>
<varlistentry>
- <term>OWNER</term>
+ <term><literal>OWNER</literal></term>
<listitem>
<para>
- This form changes the owner of the table, index, sequence or view to the
+ This form changes the owner of the table, index, sequence, or view to the
specified user.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>CLUSTER</term>
+ <term><literal>CLUSTER</literal></term>
<listitem>
<para>
This form marks a table for future <xref linkend="SQL-CLUSTER" endterm="sql-cluster-title">
</varlistentry>
</variablelist>
+ </para>
<para>
You must own the table to use <command>ALTER TABLE</>; except for
<command>ALTER TABLE OWNER</>, which may only be executed by a superuser.
</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Parameters</title>
+
+ <variablelist>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">table</replaceable></term>
+ <listitem>
+ <para>
+ The name (possibly schema-qualified) of an existing table to
+ alter. If <literal>ONLY</> is specified, only that table is
+ altered. If <literal>ONLY</> is not specified, the table and all
+ its descendant tables (if any) are updated. <literal>*</> can be
+ appended to the table name to indicate that descendant tables are
+ to be altered, but in the current version, this is the default
+ behavior. (In releases before 7.1, <literal>ONLY</> was the
+ default behavior. The default can be altered by changing the
+ configuration parameter <varname>sql_inheritance</varname>.)
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">column</replaceable></term>
+ <listitem>
+ <para>
+ Name of a new or existing column.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">type</replaceable></term>
+ <listitem>
+ <para>
+ Data type of the new column.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">new_column</replaceable></term>
+ <listitem>
+ <para>
+ New name for an existing column.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">new_table</replaceable></term>
+ <listitem>
+ <para>
+ New name for the table.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">table_constraint</replaceable></term>
+ <listitem>
+ <para>
+ New table constraint for the table.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">constraint_name</replaceable></term>
+ <listitem>
+ <para>
+ Name of an existing constraint to drop.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">new_owner</replaceable></term>
+ <listitem>
+ <para>
+ The user name of the new owner of the table.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">index_name</replaceable></term>
+ <listitem>
+ <para>
+ The index name on which the table should be marked for clustering.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>CASCADE</literal></term>
+ <listitem>
+ <para>
+ Automatically drop objects that depend on the dropped column
+ or constraint (for example, views referencing the column).
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>RESTRICT</literal></term>
+ <listitem>
+ <para>
+ Refuse to drop the column or constraint if there are any dependent
+ objects. This is the default behavior.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Diagnostics</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><computeroutput>ALTER TABLE</computeroutput></term>
+ <listitem>
+ <para>
+ Message returned if successful.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><computeroutput>ERROR</computeroutput></term>
+ <listitem>
+ <para>
+ Message returned if table or column does not exist.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Notes</title>
- <refsect2 id="R2-SQL-ALTERTABLE-3">
- <refsect2info>
- <date>1998-04-15</date>
- </refsect2info>
- <title>
- Notes
-</title>
<para>
- The keyword <literal>COLUMN</literal> is noise and can be omitted.
+ The key word <literal>COLUMN</literal> is noise and can be omitted.
</para>
<para>
In the current implementation of <literal>ADD COLUMN</literal>,
- default and NOT NULL clauses for the new column are not supported.
- The new column always comes into being with all values NULL.
+ default and <literal>NOT NULL</> clauses for the new column are not supported.
+ The new column always comes into being with all values null.
You can use the <literal>SET DEFAULT</literal> form
of <command>ALTER TABLE</command> to set the default afterward.
(You may also want to update the already existing rows to the
</para>
<para>
- The <literal>DROP COLUMN</literal> command does not physically remove
+ The <literal>DROP COLUMN</literal> form does not physically remove
the column, but simply makes it invisible to SQL operations. Subsequent
- inserts and updates of the table will store a NULL for the column.
+ insert and update operations in the table will store a null value for the column.
Thus, dropping a column is quick but it will not immediately reduce the
on-disk size of your table, as the space occupied
by the dropped column is not reclaimed. The space will be
reclaimed over time as existing rows are updated.
To reclaim the space at once, do a dummy <command>UPDATE</> of all rows
and then vacuum, as in:
+<programlisting>
UPDATE table SET col = col;
VACUUM FULL table;
- </programlisting>
+</programlisting>
</para>
<para>
- If a table has any descendant tables, it is not permitted to ADD
- or RENAME a column in the parent table without doing the same to
- the descendants --- that is, <command>ALTER TABLE ONLY</command>
+ If a table has any descendant tables, it is not permitted to add
+ or rename a column in the parent table without doing the same to
+ the descendants. That is, <command>ALTER TABLE ONLY</command>
will be rejected. This ensures that the descendants always have
columns matching the parent.
</para>
</para>
<para>
- Changing any part of the schema of a system
- catalog is not permitted.
+ Changing any part of a system catalog table is not permitted.
</para>
<para>
Refer to <command>CREATE TABLE</command> for a further description
- of valid arguments. <xref linkend="ddl"> has further information on
+ of valid parameters. <xref linkend="ddl"> has further information on
inheritance.
</para>
- </refsect2>
</refsect1>
- <refsect1 id="R1-SQL-ALTERTABLE-2">
- <title>
- Usage
- </title>
+ <refsect1>
+ <title>Examples</title>
+
<para>
To add a column of type <type>varchar</type> to a table:
-ALTER TABLE distributors ADD COLUMN address VARCHAR(30);
- </programlisting>
+<programlisting>
+ALTER TABLE distributors ADD COLUMN address varchar(30);
+</programlisting>
</para>
<para>
To drop a column from a table:
+<programlisting>
ALTER TABLE distributors DROP COLUMN address RESTRICT;
- </programlisting>
+</programlisting>
</para>
<para>
To rename an existing column:
+<programlisting>
ALTER TABLE distributors RENAME COLUMN address TO city;
- </programlisting>
+</programlisting>
</para>
<para>
To rename an existing table:
+<programlisting>
ALTER TABLE distributors RENAME TO suppliers;
- </programlisting>
+</programlisting>
</para>
<para>
- To add a NOT NULL constraint to a column:
+ To add a not-null constraint to a column:
+<programlisting>
ALTER TABLE distributors ALTER COLUMN street SET NOT NULL;
- </programlisting>
- To remove a NOT NULL constraint from a column:
+</programlisting>
+ To remove a not-null constraint from a column:
+<programlisting>
ALTER TABLE distributors ALTER COLUMN street DROP NOT NULL;
- </programlisting>
+</programlisting>
</para>
<para>
To add a check constraint to a table:
+<programlisting>
ALTER TABLE distributors ADD CONSTRAINT zipchk CHECK (char_length(zipcode) = 5);
- </programlisting>
+</programlisting>
</para>
<para>
To remove a check constraint from a table and all its children:
+<programlisting>
ALTER TABLE distributors DROP CONSTRAINT zipchk;
- </programlisting>
+</programlisting>
</para>
<para>
To add a foreign key constraint to a table:
-ALTER TABLE distributors ADD CONSTRAINT distfk FOREIGN KEY (address) REFERENCES addresses(address) MATCH FULL;
- </programlisting>
+<programlisting>
+ALTER TABLE distributors ADD CONSTRAINT distfk FOREIGN KEY (address) REFERENCES addresses (address) MATCH FULL;
+</programlisting>
</para>
<para>
To add a (multicolumn) unique constraint to a table:
+<programlisting>
ALTER TABLE distributors ADD CONSTRAINT dist_id_zipcode_key UNIQUE (dist_id, zipcode);
- </programlisting>
+</programlisting>
</para>
<para>
To add an automatically named primary key constraint to a table, noting
that a table can only ever have one primary key:
+<programlisting>
ALTER TABLE distributors ADD PRIMARY KEY (dist_id);
- </programlisting>
+</programlisting>
</para>
</refsect1>
- <refsect1 id="R1-SQL-ALTERTABLE-3">
- <title>
- Compatibility
- </title>
-
- <refsect2 id="R2-SQL-ALTERTABLE-4">
- <refsect2info>
- <date>1998-04-15</date>
- </refsect2info>
- <title>SQL92</title>
- <para>
- The <literal>ADD COLUMN</literal> form is compliant with the exception that
- it does not support defaults and NOT NULL constraints, as explained above.
- The <literal>ALTER COLUMN</literal> form is in full compliance.
- </para>
+ <refsect1>
+ <title>Compatibility</title>
- <para>
- The clauses to rename tables, columns, indexes, and sequences are
- <productname>PostgreSQL</productname> extensions from SQL92.
- </para>
+ <para>
+ The <literal>ADD COLUMN</literal> form conforms with the SQL
+ standard, with the exception that it does not support defaults and
+ not-null constraints, as explained above. The <literal>ALTER
+ COLUMN</literal> form is in full conformance.
+ </para>
- <para>
- <command>ALTER TABLE DROP COLUMN</> can be used to drop the only column
- of a table, leaving a zero-column table. This is an extension from SQL92,
- which disallows zero-column tables.
- </para>
-
- </refsect2>
+ <para>
+ The clauses to rename tables, columns, indexes, views, and sequences are
+ <productname>PostgreSQL</productname> extensions of the SQL standard.
+ </para>
+
+ <para>
+ <command>ALTER TABLE DROP COLUMN</> can be used to drop the only
+ column of a table, leaving a zero-column table. This is an
+ extension of SQL, which disallows zero-column tables.
+ </para>
</refsect1>
</refentry>
<!--
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/alter_trigger.sgml,v 1.4 2003/04/15 13:25:08 petere Exp $
PostgreSQL documentation
-->
<refentry id="SQL-ALTERTRIGGER">
<refmeta>
- <refentrytitle id="sql-altertrigger-title">
- ALTER TRIGGER
- </refentrytitle>
+ <refentrytitle id="sql-altertrigger-title">ALTER TRIGGER</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
+
<refnamediv>
- <refname>
- ALTER TRIGGER
- </refname>
- <refpurpose>
- change the definition of a trigger
- </refpurpose>
+ <refname>ALTER TRIGGER</refname>
+ <refpurpose>change the definition of a trigger</refpurpose>
</refnamediv>
+
<refsynopsisdiv>
- <refsynopsisdivinfo>
- <date>2002-04-19</date>
- </refsynopsisdivinfo>
- <synopsis>
+<synopsis>
ALTER TRIGGER <replaceable class="PARAMETER">trigger</replaceable> ON <replaceable class="PARAMETER">table</replaceable>
RENAME TO <replaceable class="PARAMETER">newname</replaceable>
- </synopsis>
-
- <refsect2 id="R2-SQL-ALTERTRIGGER-1">
- <refsect2info>
- <date>2002-04-19</date>
- </refsect2info>
- <title>
- Inputs
- </title>
- <para>
- <variablelist>
-
- <varlistentry>
- <term><replaceable class="PARAMETER"> trigger </replaceable></term>
- <listitem>
- <para>
- The name of an existing trigger to alter.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><replaceable class="PARAMETER"> table </replaceable></term>
- <listitem>
- <para>
- The name of the table on which this trigger acts.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><replaceable class="PARAMETER"> newname </replaceable></term>
- <listitem>
- <para>
- New name for the existing trigger.
- </para>
- </listitem>
- </varlistentry>
-
- </variablelist>
- </para>
- </refsect2>
-
- <refsect2 id="R2-SQL-ALTERTRIGGER-2">
- <refsect2info>
- <date>2002-04-19</date>
- </refsect2info>
- <title>
- Outputs
- </title>
- <para>
-
- <variablelist>
- <varlistentry>
- <term><computeroutput>ALTER TRIGGER</computeroutput></term>
- <listitem>
- <para>
- Message returned from trigger renaming.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><computeroutput>ERROR</computeroutput></term>
- <listitem>
- <para>
- Message returned if trigger is not available, or new name is a duplicate of another existing trigger on the table.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
- </refsect2>
+</synopsis>
</refsynopsisdiv>
- <refsect1 id="R1-SQL-ALTERTRIGGER-1">
- <refsect1info>
- <date>2002-04-19</date>
- </refsect1info>
- <title>
- Description
- </title>
+ <refsect1>
+ <title>Description</title>
+
<para>
- <command>ALTER TRIGGER</command> changes the definition of an existing trigger.
- The <literal>RENAME</literal> clause causes the name of a trigger on the given table
- to change without otherwise changing the trigger definition.
+ <command>ALTER TRIGGER</command> changes properties of an existing
+ trigger. The <literal>RENAME</literal> clause changes the name of
+ the given trigger without otherwise changing the trigger
+ definition.
</para>
<para>
- You must own the table on which the trigger acts in order to change its properties.
+ You must own the table on which the trigger acts to be allowed to change its properties.
</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Parameter</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><replaceable class="PARAMETER">trigger</replaceable></term>
+ <listitem>
+ <para>
+ The name of an existing trigger to alter.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">table</replaceable></term>
+ <listitem>
+ <para>
+ The name of the table on which this trigger acts.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">newname</replaceable></term>
+ <listitem>
+ <para>
+ The new name for the trigger.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
- <refsect2 id="R2-SQL-ALTERTRIGGER-3">
- <refsect2info>
- <date>2002-04-19</date>
- </refsect2info>
- <title>
- Notes
- </title>
- <para>
- Refer to <command>CREATE TRIGGER</command> for a further description
- of valid arguments.
- </para>
- </refsect2>
+ <refsect1>
+ <title>Diagnostics</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><computeroutput>ALTER TRIGGER</computeroutput></term>
+ <listitem>
+ <para>
+ Message returned if successful.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><computeroutput>ERROR</computeroutput></term>
+ <listitem>
+ <para>
+ If the trigger does not exist, or the new name is a duplicate of
+ another existing trigger on the table.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
</refsect1>
- <refsect1 id="R1-SQL-ALTERTRIGGER-2">
- <title>
- Usage
- </title>
+ <refsect1>
+ <title>Examples</title>
+
<para>
To rename an existing trigger:
+<programlisting>
ALTER TRIGGER emp_stamp ON emp RENAME TO emp_track_chgs;
- </programlisting>
+</programlisting>
</para>
</refsect1>
- <refsect1 id="R1-SQL-ALTERTRIGGER-3">
- <title>
- Compatibility
- </title>
-
- <refsect2 id="R2-SQL-ALTERTRIGGER-4">
- <refsect2info>
- <date>2002-04-19</date>
- </refsect2info>
- <title>SQL92</title>
- <para>
- <command>ALTER TRIGGER</command> is a <productname>PostgreSQL</>
- extension of SQL92.
- </para>
- </refsect2>
+ <refsect1>
+ <title>Compatibility</title>
+
+ <para>
+ <command>ALTER TRIGGER</command> is a <productname>PostgreSQL</>
+ extension of the SQL standard.
+ </para>
</refsect1>
</refentry>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/alter_user.sgml,v 1.26 2003/03/25 16:15:39 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/alter_user.sgml,v 1.27 2003/04/15 13:25:08 petere Exp $
PostgreSQL documentation
-->
where <replaceable class="PARAMETER">option</replaceable> can be:
- [ ENCRYPTED | UNENCRYPTED ] PASSWORD '<replaceable class="PARAMETER">password</replaceable>'
+ [ ENCRYPTED | UNENCRYPTED ] PASSWORD '<replaceable class="PARAMETER">password</replaceable>'
| CREATEDB | NOCREATEDB
| CREATEUSER | NOCREATEUSER
| VALID UNTIL '<replaceable class="PARAMETER">abstime</replaceable>'
<para>
The first variant of this command in the synopsis changes certain
global user privileges and authentication settings. (See below for
- details.) Only a database superuser can change privileges and
- password expiration with this command. Ordinary users can only
+ details.) Only a database superuser can change these privileges and
+ the password expiration with this command. Ordinary users can only
change their own password.
</para>
a specified configuration variable. Whenever the user subsequently
starts a new session, the specified value becomes the session default,
overriding whatever setting is present in <filename>postgresql.conf</>
- or has been received from the postmaster.
+ or has been received from the <command>postmaster</command> command line.
Ordinary users can change their own session defaults.
Superusers can change anyone's session defaults.
</para>
+ </refsect1>
- <refsect2>
- <title>Parameters</title>
+ <refsect1>
+ <title>Parameters</title>
- <para>
<variablelist>
<varlistentry>
<term><replaceable class="PARAMETER">username</replaceable></term>
<listitem>
<para>
These clauses define a user's ability to create databases. If
- <literal>CREATEDB</literal> is specified, the user being
- defined will be allowed to create his own databases. Using
+ <literal>CREATEDB</literal> is specified, the user
+ will be allowed to create his own databases. Using
<literal>NOCREATEDB</literal> will deny a user the ability to
create databases.
</para>
<para>
The date (and, optionally, the time)
at which this user's password is to expire. To set the password
- never to expire, use 'infinity'.
+ never to expire, use <literal>'infinity'</>.
</para>
</listitem>
</varlistentry>
</listitem>
</varlistentry>
</variablelist>
- </para>
- </refsect2>
</refsect1>
<refsect1>
<title>Diagnostics</title>
- <para>
<variablelist>
<varlistentry>
<term><computeroutput>ALTER USER</computeroutput></term>
<listitem>
<para>
Error message returned if the specified user is not known to
- the database.
+ the database system.
</para>
</listitem>
</varlistentry>
</variablelist>
- </para>
</refsect1>
<refsect1>
<para>
Change a user's valid until date, specifying that his
- authorization should expire at midday on 4th May 1998 using
+ authorization should expire at midday on 4th May 2005 using
the time zone which is one hour ahead of <acronym>UTC</>:
<programlisting>
-ALTER USER chris VALID UNTIL 'May 4 12:00:00 1998 +1';
+ALTER USER chris VALID UNTIL 'May 4 12:00:00 2005 +1';
</programlisting>
</para>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/analyze.sgml,v 1.11 2003/03/25 16:15:39 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/analyze.sgml,v 1.12 2003/04/15 13:25:08 petere Exp $
PostgreSQL documentation
-->
<refentrytitle id="sql-analyze-title">ANALYZE</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
+
<refnamediv>
- <refname>
- ANALYZE
- </refname>
- <refpurpose>
- collect statistics about a database
- </refpurpose>
+ <refname>ANALYZE</refname>
+ <refpurpose>collect statistics about a database</refpurpose>
</refnamediv>
+
<refsynopsisdiv>
- <refsynopsisdivinfo>
- <date>2001-05-04</date>
- </refsynopsisdivinfo>
- <synopsis>
+<synopsis>
ANALYZE [ VERBOSE ] [ <replaceable class="PARAMETER">table</replaceable> [ (<replaceable class="PARAMETER">column</replaceable> [, ...] ) ] ]
- </synopsis>
-
- <refsect2 id="R2-SQL-ANALYZE-1">
- <refsect2info>
- <date>2001-05-04</date>
- </refsect2info>
- <title>
- Inputs
- </title>
-
- <para>
- <variablelist>
- <varlistentry>
- <term>VERBOSE</term>
- <listitem>
- <para>
- Enables display of progress messages.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><replaceable class="PARAMETER">table</replaceable></term>
- <listitem>
- <para>
- The name (possibly schema-qualified) of a specific table to
- analyze. Defaults to all tables in the current database.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><replaceable class="PARAMETER">column</replaceable></term>
- <listitem>
- <para>
- The name of a specific column to analyze. Defaults to all columns.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
- </refsect2>
-
- <refsect2 id="R2-SQL-ANALYZE-2">
- <refsect2info>
- <date>2001-05-04</date>
- </refsect2info>
- <title>
- Outputs
- </title>
- <para>
-
- <variablelist>
- <varlistentry>
- <term><computeroutput>
-<returnvalue>ANALYZE</returnvalue>
- </computeroutput></term>
- <listitem>
- <para>
- The command is complete.
- </para>
- </listitem>
- </varlistentry>
-
- </variablelist>
- </para>
- </refsect2>
+</synopsis>
</refsynopsisdiv>
- <refsect1 id="R1-SQL-ANALYZE-1">
- <refsect1info>
- <date>2001-05-04</date>
- </refsect1info>
- <title>
- Description
- </title>
+ <refsect1>
+ <title>Description</title>
+
<para>
<command>ANALYZE</command> collects statistics about the contents of
- <productname>PostgreSQL</productname> tables, and stores the results in
+ tables in the database, and stores the results in
the system table <literal>pg_statistic</literal>. Subsequently,
the query planner uses the statistics to help determine the most efficient
execution plans for queries.
With no parameter, <command>ANALYZE</command> examines every table in the
current database. With a parameter, <command>ANALYZE</command> examines
only that table. It is further possible to give a list of column names,
- in which case only the statistics for those columns are updated.
+ in which case only the statistics for those columns are collected.
</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Parameters</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><literal>VERBOSE</literal></term>
+ <listitem>
+ <para>
+ Enables display of progress messages.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">table</replaceable></term>
+ <listitem>
+ <para>
+ The name (possibly schema-qualified) of a specific table to
+ analyze. Defaults to all tables in the current database.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">column</replaceable></term>
+ <listitem>
+ <para>
+ The name of a specific column to analyze. Defaults to all columns.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
- <refsect2 id="R2-SQL-ANALYZE-3">
- <refsect2info>
- <date>2001-05-04</date>
- </refsect2info>
- <title>
- Notes
- </title>
+ <refsect1>
+ <title>Diagnostics</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><computeroutput>ANALYZE</computeroutput></term>
+ <listitem>
+ <para>
+ The command is complete.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Notes</title>
<para>
It is a good idea to run <command>ANALYZE</command> periodically, or
<para>
For large tables, <command>ANALYZE</command> takes a random sample of the
table contents, rather than examining every row. This allows even very
- large tables to be analyzed in a small amount of time. Note however
+ large tables to be analyzed in a small amount of time. Note, however,
that the statistics are only approximate, and will change slightly each
time <command>ANALYZE</command> is run, even if the actual table contents
did not change. This may result in small changes in the planner's
The extent of analysis can be controlled by adjusting the
<literal>default_statistics_target</> parameter variable, or on a
column-by-column basis by setting the per-column
- statistics target with <command>ALTER TABLE ALTER COLUMN SET
+ statistics target with <command>ALTER TABLE ... ALTER COLUMN ... SET
STATISTICS</command> (see
<xref linkend="sql-altertable" endterm="sql-altertable-title">). The
target value sets the maximum number of entries in the most-common-value
in <literal>pg_statistic</literal>.
In particular, setting the statistics target to zero disables collection of
statistics for that column. It may be useful to do that for columns that
- are never used as part of the WHERE, GROUP BY, or ORDER BY clauses of
+ are never used as part of the <literal>WHERE</>, <literal>GROUP BY</>, or <literal>ORDER BY</> clauses of
queries, since the planner will have no use for statistics on such columns.
</para>
the target causes a proportional increase in the time and space needed
to do <command>ANALYZE</command>.
</para>
-
- </refsect2>
</refsect1>
- <refsect1 id="R1-SQL-ANALYZE-3">
- <title>
- Compatibility
- </title>
-
- <refsect2 id="R2-SQL-ANALYZE-4">
- <refsect2info>
- <date>2001-05-04</date>
- </refsect2info>
- <title>
- SQL92
- </title>
- <para>
- There is no <command>ANALYZE</command> statement in <acronym>SQL92</acronym>.
- </para>
- </refsect2>
+ <refsect1>
+ <title>Compatibility</title>
+
+ <para>
+ There is no <command>ANALYZE</command> statement in the SQL standard.
+ </para>
</refsect1>
</refentry>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/begin.sgml,v 1.22 2003/03/25 16:15:39 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/begin.sgml,v 1.23 2003/04/15 13:25:08 petere Exp $
PostgreSQL documentation
-->
<refentrytitle id="SQL-BEGIN-TITLE">BEGIN</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
+
<refnamediv>
- <refname>
- BEGIN
- </refname>
- <refpurpose>
- start a transaction block
- </refpurpose>
-
- </refnamediv>
+ <refname>BEGIN</refname>
+ <refpurpose>start a transaction block</refpurpose>
+ </refnamediv>
+
<refsynopsisdiv>
- <refsynopsisdivinfo>
- <date>1999-07-20</date>
- </refsynopsisdivinfo>
- <synopsis>
+<synopsis>
BEGIN [ WORK | TRANSACTION ]
- </synopsis>
-
- <refsect2 id="R2-SQL-BEGIN-1">
- <refsect2info>
- <date>1999-06-11</date>
- </refsect2info>
- <title>
- Inputs
- </title>
- <para>
-
- <variablelist>
- <varlistentry>
- <term>WORK</term>
- <term>TRANSACTION</term>
- <listitem>
- <para>
- Optional keywords. They have no effect.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
- </refsect2>
-
- <refsect2 id="R2-SQL-BEGIN-2">
- <refsect2info>
- <date>1999-06-11</date>
- </refsect2info>
- <title>
- Outputs
- </title>
-
- <para>
- <variablelist>
- <varlistentry>
- <term><computeroutput>
-BEGIN
- </computeroutput></term>
- <listitem>
- <para>
- This signifies that a new transaction has been started.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><computeroutput>
-WARNING: BEGIN: already a transaction in progress
- </computeroutput></term>
- <listitem>
- <para>
- This indicates that a transaction was already in progress.
- The current transaction is not affected.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
- </refsect2>
+</synopsis>
</refsynopsisdiv>
- <refsect1 id="R1-SQL-BEGIN-1">
- <refsect1info>
- <date>1999-06-11</date>
- </refsect1info>
- <title>
- Description
- </title>
+ <refsect1>
+ <title>Description</title>
<para>
- By default, <productname>PostgreSQL</productname> executes transactions
- in <firstterm>unchained mode</firstterm>
- (also known as <quote>autocommit</quote> in other database
- systems).
- In other words, each user statement is executed in its own transaction
- and a commit is implicitly performed at the end of the statement
- (if execution was successful, otherwise a rollback is done).
- <command>BEGIN</command> initiates a user transaction in chained mode,
- i.e., all user statements after <command>BEGIN</command> command will
- be executed in a single transaction until an explicit
- <xref linkend="sql-commit" endterm="sql-commit-title"> or
- <xref linkend="sql-rollback" endterm="sql-rollback-title">.
- Statements are executed more quickly in chained mode,
- because transaction start/commit requires significant CPU and disk
- activity. Execution of multiple statements inside a transaction
- is also useful to ensure consistency when changing several
- related tables: other clients will be unable to see the intermediate
- states wherein not all the related updates have been done.
+ By default, <productname>PostgreSQL</productname> executes
+ transactions in <quote>autocommit</quote> mode, that is, each
+ statement is executed in its own transaction and a commit is
+ implicitly performed at the end of the statement (if execution was
+ successful, otherwise a rollback is done).
+ <command>BEGIN</command> initiates a transaction block, that is,
+ all statements after <command>BEGIN</command> command will be
+ executed in a single transaction until an explicit <xref
+ linkend="sql-commit" endterm="sql-commit-title"> or <xref
+ linkend="sql-rollback" endterm="sql-rollback-title">. Statements
+ are executed more quickly in a transaction block, because
+ transaction start/commit requires significant CPU and disk
+ activity. Execution of multiple statements inside a transaction is
+ also useful to ensure consistency when changing several related
+ tables: other sessions will be unable to see the intermediate states
+ wherein not all the related updates have been done.
</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Parameters</title>
- <para>
- The default transaction isolation level in
- <productname>PostgreSQL</productname>
- is READ COMMITTED, wherein each query inside the transaction sees changes
- committed before that query begins execution. So, you have to use
- <command>SET TRANSACTION ISOLATION LEVEL SERIALIZABLE</command>
- just after <command>BEGIN</command> if you need more rigorous transaction
- isolation. (Alternatively, you can change the default transaction
- isolation level; see <xref linkend="runtime-config"> for details.)
- In SERIALIZABLE mode queries will see only changes committed before
- the entire
- transaction began (actually, before execution of the first <acronym>DML</> statement
- in the transaction).
- </para>
+ <variablelist>
+ <varlistentry>
+ <term><literal>WORK</literal></term>
+ <term><literal>TRANSACTION</literal></term>
+ <listitem>
+ <para>
+ Optional key words. They have no effect.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Diagnostics</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><computeroutput>BEGIN</computeroutput></term>
+ <listitem>
+ <para>
+ This signifies that a new transaction has been started.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><computeroutput>WARNING: BEGIN: already a transaction in progress</computeroutput></term>
+ <listitem>
+ <para>
+ This indicates that a transaction was already in progress. The
+ current transaction is not affected.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Notes</title>
<para>
- Transactions have the standard <acronym>ACID</acronym>
- (atomic, consistent, isolatable, and durable) properties.
+ <xref linkend="sql-start-transaction"
+ endterm="sql-start-transaction-title"> has the same functionality
+ as <command>BEGIN</>.
</para>
-
- <refsect2 id="R2-SQL-BEGIN-3">
- <refsect2info>
- <date>1999-06-11</date>
- </refsect2info>
- <title>
- Notes
- </title>
- <para>
- <xref linkend="sql-start-transaction"
- endterm="sql-start-transaction-title"> has the same functionality
- as <command>BEGIN</>.
- </para>
- <para>
- Use <xref linkend="SQL-COMMIT" endterm="SQL-COMMIT-TITLE">
- or
- <xref linkend="SQL-ROLLBACK" endterm="SQL-ROLLBACK-TITLE">
- to terminate a transaction.
- </para>
-
- <para>
- Refer to <xref linkend="sql-lock" endterm="sql-lock-title">
- for further information
- about locking tables inside a transaction.
- </para>
+ <para>
+ Use <xref linkend="SQL-COMMIT" endterm="SQL-COMMIT-TITLE"> or
+ <xref linkend="SQL-ROLLBACK" endterm="SQL-ROLLBACK-TITLE">
+ to terminate a transaction.
+ </para>
- If you turn <varname>autocommit</> mode off, then <command>BEGIN</>
- is not required: any SQL command automatically starts a transaction.
- </para>
- </refsect2>
+ <para>
+ If you turn the configuration parameter <varname>autocommit</> off,
+ then <command>BEGIN</> is not required: any SQL command
+ automatically starts a transaction.
+ </para>
</refsect1>
- <refsect1 id="R1-SQL-BEGIN-2">
- <title>
- Usage
- </title>
+ <refsect1>
+ <title>Examples</title>
<para>
- To begin a user transaction:
+ To begin a transaction block:
-BEGIN WORK;
- </programlisting>
+<programlisting>
+BEGIN;
+</programlisting>
</para>
</refsect1>
- <refsect1 id="R1-SQL-BEGIN-3">
- <title>
- Compatibility
- </title>
-
- <refsect2 id="R2-SQL-BEGIN-4">
- <refsect2info>
- <date>1999-06-11</date>
- </refsect2info>
- <title>
- SQL92
- </title>
+ <refsect1>
+ <title>Compatibility</title>
- <para>
- <command>BEGIN</command>
- is a <productname>PostgreSQL</productname> language extension.
- There is no explicit <command>BEGIN</command>
- command in <acronym>SQL92</acronym>;
- transaction initiation is always implicit and it terminates either
- with a <command>COMMIT</command> or <command>ROLLBACK</command> statement.
-
- <note>
- <para>
- Many relational database systems offer an autocommit feature as a
- convenience.
- </para>
- </note>
- </para>
+ <para>
+ <command>BEGIN</command> is a <productname>PostgreSQL</productname>
+ language extension. There is no explicit <command>BEGIN</command>
+ command in the SQL standard; transaction initiation is
+ always implicit and it terminates either with a
+ <command>COMMIT</command> or <command>ROLLBACK</command> statement.
+ </para>
- <para>
- Incidentally, the <literal>BEGIN</literal> keyword is used for a different
- purpose in embedded SQL. You are advised to be careful about the transaction
- semantics when porting database applications.
- </para>
+ <para>
+ Other relational database systems may offer an autocommit feature
+ as a convenience.
+ </para>
- <acronym>SQL92</acronym> also requires SERIALIZABLE to be the default
- transaction isolation level.
- </para>
- </refsect2>
+ <para>
+ Incidentally, the <literal>BEGIN</literal> key word is used for a
+ different purpose in embedded SQL. You are advised to be careful
+ about the transaction semantics when porting database applications.
+ </para>
</refsect1>
</refentry>
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/checkpoint.sgml,v 1.8 2003/03/25 16:15:39 petere Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/checkpoint.sgml,v 1.9 2003/04/15 13:25:08 petere Exp $ -->
<refentry id="sql-checkpoint">
<refmeta>
Write-Ahead Logging (WAL) puts a checkpoint in the transaction log
every so often. (To adjust the automatic checkpoint interval, see
the run-time
- configuration options <parameter>CHECKPOINT_SEGMENTS</parameter>
- and <parameter>CHECKPOINT_TIMEOUT</parameter>.)
+ configuration options <varname>checkpoint_segments</varname>
+ and <varname>checkpoint_timeout</varname>.)
The <command>CHECKPOINT</command> command forces an immediate checkpoint
when the command is issued, without waiting for a scheduled checkpoint.
</para>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/close.sgml,v 1.13 2002/05/18 15:44:47 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/close.sgml,v 1.14 2003/04/15 13:25:08 petere Exp $
PostgreSQL documentation
-->
<refentrytitle id="SQL-CLOSE-TITLE">CLOSE</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
+
<refnamediv>
- <refname>
- CLOSE
- </refname>
- <refpurpose>
- close a cursor
- </refpurpose>
+ <refname>CLOSE</refname>
+ <refpurpose>close a cursor</refpurpose>
</refnamediv>
+
<refsynopsisdiv>
- <refsynopsisdivinfo>
- <date>1999-07-20</date>
- </refsynopsisdivinfo>
- <synopsis>
+<synopsis>
CLOSE <replaceable class="PARAMETER">cursor</replaceable>
- </synopsis>
-
- <refsect2 id="R2-SQL-CLOSE-1">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- Inputs
- </title>
- <para>
-
- <variablelist>
- <varlistentry>
- <term><replaceable class="PARAMETER">cursor</replaceable></term>
- <listitem>
- <para>
- The name of an open cursor to close.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
- </refsect2>
-
- <refsect2 id="R2-SQL-CLOSE-2">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- Outputs
- </title>
- <para>
-
- <variablelist>
- <varlistentry>
- <term><computeroutput>
-CLOSE CURSOR
- </computeroutput></term>
- <listitem>
- <para>
- Message returned if the cursor is successfully closed.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><computeroutput>
-WARNING: PerformPortalClose: portal "<replaceable class="PARAMETER">cursor</replaceable>" not found
- </computeroutput></term>
- <listitem>
- <para>
- This warning is given if
- <replaceable class="PARAMETER">cursor</replaceable> is not
- declared or has already been closed.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
- </refsect2>
+</synopsis>
</refsynopsisdiv>
- <refsect1 id="R1-SQL-CLOSE-1">
- <refsect1info>
- <date>1998-09-08</date>
- </refsect1info>
- <title>
- Description
- </title>
+ <refsect1>
+ <title>Description</title>
+
<para>
<command>CLOSE</command> frees the resources associated with an open cursor.
After the cursor is closed, no subsequent operations
are allowed on it. A cursor should be closed when it is
no longer needed.
</para>
+
<para>
- An implicit close is executed for every open cursor when a
- transaction is terminated by <command>COMMIT</command>
- or <command>ROLLBACK</command>.
+ Every open cursor is implicitly closed when a transaction is
+ terminated by <command>COMMIT</command> or
+ <command>ROLLBACK</command>.
</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Parameters</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><replaceable class="PARAMETER">cursor</replaceable></term>
+ <listitem>
+ <para>
+ The name of an open cursor to close.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
- <refsect2 id="R2-SQL-CLOSE-3">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- Notes
- </title>
- <para>
- <productname>PostgreSQL</productname> does not have
- an explicit <command>OPEN</command> cursor statement;
- a cursor is considered open when it is declared.
- Use the <command>DECLARE</command> statement to declare a cursor.
- </para>
- </refsect2>
+ <refsect1>
+ <title>Diagnostics</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><computeroutput>CLOSE CURSOR</computeroutput></term>
+ <listitem>
+ <para>
+ Message returned if the cursor is successfully closed.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><computeroutput>WARNING: PerformPortalClose: portal "<replaceable class="PARAMETER">cursor</replaceable>" not found</computeroutput></term>
+ <listitem>
+ <para>
+ This warning is given if <replaceable
+ class="PARAMETER">cursor</replaceable> is not declared or has
+ already been closed.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
</refsect1>
- <refsect1 id="R1-SQL-CLOSE-2">
- <title>
- Usage
- </title>
+ <refsect1>
+ <title>Notes</title>
+
<para>
- Close the cursor <literal>liahona</literal>:
+ <productname>PostgreSQL</productname> does not have an explicit
+ <command>OPEN</command> cursor statement; a cursor is considered
+ open when it is declared. Use the <command>DECLARE</command>
+ statement to declare a cursor.
</para>
- <programlisting>
+ </refsect1>
+
+ <refsect1>
+ <title>Examples</title>
+
+ <para>
+ Close the cursor <literal>liahona</literal>:
+<programlisting>
CLOSE liahona;
- </programlisting>
+</programlisting>
+ </para>
</refsect1>
- <refsect1 id="R1-SQL-CLOSE-3">
- <title>
- Compatibility
- </title>
+ <refsect1>
+ <title>Compatibility</title>
- <refsect2 id="R2-SQL-CLOSE-4">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- SQL92
- </title>
- <para>
- <command>CLOSE</command> is fully compatible with SQL92.
- </para>
- </refsect2>
+ <para>
+ <command>CLOSE</command> is fully conforming with the SQL standard.
+ </para>
</refsect1>
</refentry>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/cluster.sgml,v 1.25 2003/03/25 16:15:39 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/cluster.sgml,v 1.26 2003/04/15 13:25:08 petere Exp $
PostgreSQL documentation
-->
<refentrytitle id="sql-cluster-title">CLUSTER</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
+
<refnamediv>
- <refname>
- CLUSTER
- </refname>
- <refpurpose>
- cluster a table according to an index
- </refpurpose>
+ <refname>CLUSTER</refname>
+ <refpurpose>cluster a table according to an index</refpurpose>
</refnamediv>
+
<refsynopsisdiv>
- <refsynopsisdivinfo>
- <date>1999-07-20</date>
- </refsynopsisdivinfo>
- <synopsis>
+<synopsis>
CLUSTER <replaceable class="PARAMETER">indexname</replaceable> ON <replaceable class="PARAMETER">tablename</replaceable>
CLUSTER <replaceable class="PARAMETER">tablename</replaceable>
CLUSTER
- </synopsis>
-
- <refsect2 id="R2-SQL-CLUSTER-1">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- Inputs
- </title>
- <para>
- </para>
- <variablelist>
- <varlistentry>
- <term><replaceable class="PARAMETER">indexname</replaceable></term>
- <listitem>
- <para>
- The name of an index.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><replaceable class="PARAMETER">table</replaceable></term>
- <listitem>
- <para>
- The name (possibly schema-qualified) of a table.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </refsect2>
-
- <refsect2 id="R2-SQL-CLUSTER-2">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- Outputs
- </title>
- <para>
-
- <variablelist>
- <varlistentry>
- <term><computeroutput>
-CLUSTER
- </computeroutput></term>
- <listitem>
- <para>
- The clustering was done successfully.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
- </refsect2>
+</synopsis>
</refsynopsisdiv>
- <refsect1 id="R1-SQL-CLUSTER-1">
- <refsect1info>
- <date>1998-09-08</date>
- </refsect1info>
- <title>
- Description
- </title>
+ <refsect1>
+ <title>Description</title>
+
<para>
<command>CLUSTER</command> instructs <productname>PostgreSQL</productname>
to cluster the table specified
- by <replaceable class="parameter">table</replaceable>
+ by <replaceable class="parameter">tablename</replaceable>
based on the index specified by
<replaceable class="parameter">indexname</replaceable>. The index must
already have been defined on
based on the index information. Clustering is a one-time operation:
when the table is subsequently updated, the changes are
not clustered. That is, no attempt is made to store new or
- updated tuples according to their index order. If one wishes, one can
- periodically re-cluster by issuing the command again.
+ updated rows according to their index order. If one wishes, one can
+ periodically recluster by issuing the command again.
</para>
<para>
When a table is clustered, <productname>PostgreSQL</productname>
remembers on which index it was clustered. The form
<command>CLUSTER <replaceable class="parameter">tablename</replaceable></command>,
- re-clusters the table on the same index that it was clustered before.
+ reclusters the table on the same index that it was clustered before.
</para>
<para>
- <command>CLUSTER</command> without any parameter re-clusters all the tables
+ <command>CLUSTER</command> without any parameter reclusters all the tables
in the
current database that the calling user owns, or all tables if called
by a superuser. (Never-clustered tables are not included.) This
table until the <command>CLUSTER</command> is finished. See
<xref linkend="explicit-locking"> for more information on database locking.
</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Parameter</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><replaceable class="PARAMETER">indexname</replaceable></term>
+ <listitem>
+ <para>
+ The name of an index.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">tablename</replaceable></term>
+ <listitem>
+ <para>
+ The name (possibly schema-qualified) of a table.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Diagnostics</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><computeroutput>CLUSTER</computeroutput></term>
+ <listitem>
+ <para>
+ The clustering was done successfully.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
- <refsect2 id="R2-SQL-CLUSTER-3">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- Notes
- </title>
+ <refsect1>
+ <title>Notes</title>
<para>
In cases where you are accessing single rows randomly
- within a table, the actual order of the data in the heap
+ within a table, the actual order of the data in the
table is unimportant. However, if you tend to access some
data more than others, and there is an index that groups
them together, you will benefit from using <command>CLUSTER</command>.
- </para>
-
- <para>
- Another place where <command>CLUSTER</command> is helpful is in
- cases where you use an
- index to pull out several rows from a table. If you are
- requesting a range of indexed values from a table, or a
+ If you are requesting a range of indexed values from a table, or a
single indexed value that has multiple rows that match,
<command>CLUSTER</command> will help because once the index identifies the
heap page for the first row that matches, all other rows
that match are probably already on the same heap page,
- saving disk accesses and speeding up the query.
+ and so you save disk accesses and speed up the query.
</para>
<para>
sizes.
</para>
- <para>
- <command>CLUSTER</command> preserves <command>GRANT</command>,
- inheritance, index, foreign key, and other ancillary information
- about the table.
- </para>
-
<para>
Because <command>CLUSTER</command> remembers the clustering information,
one can cluster the tables one wants clustered manually the first time, and
setup a timed event similar to <command>VACUUM</command> so that the tables
- are periodically re-clustered.
+ are periodically reclustered.
</para>
<para>
- Because the optimizer records statistics about the ordering of tables, it
+ Because the planner records statistics about the ordering of tables, it
is advisable to run <command>ANALYZE</command> on the newly clustered
- table. Otherwise, the optimizer may make poor choices of query plans.
+ table. Otherwise, the planner may make poor choices of query plans.
</para>
<para>
but the majority of a big table will not fit in the cache.)
The other way to cluster a table is to use
-SELECT <replaceable class="parameter">columnlist</replaceable> INTO TABLE <replaceable class="parameter">newtable</replaceable>
- FROM <replaceable class="parameter">table</replaceable> ORDER BY <replaceable class="parameter">columnlist</replaceable>
- </programlisting>
+<programlisting>
+CREATE TABLE <replaceable class="parameter">newtable</replaceable> AS
+ SELECT <replaceable class="parameter">columnlist</replaceable> FROM <replaceable class="parameter">table</replaceable> ORDER BY <replaceable class="parameter">columnlist</replaceable>;
+</programlisting>
which uses the <productname>PostgreSQL</productname> sorting code in
- the ORDER BY clause to create the desired order; this is usually much
+ the <literal>ORDER BY</literal> clause to create the desired order; this is usually much
faster than an index scan for
unordered data. You then drop the old table, use
- <command>ALTER TABLE...RENAME</command>
+ <command>ALTER TABLE ... RENAME</command>
to rename <replaceable class="parameter">newtable</replaceable> to the old name, and
recreate the table's indexes. However, this approach does not preserve
OIDs, constraints, foreign key relationships, granted privileges, and
other ancillary properties of the table --- all such items must be
manually recreated.
</para>
-
- </refsect2>
</refsect1>
- <refsect1 id="R1-SQL-CLUSTER-2">
- <title>
- Usage
- </title>
+ <refsect1>
+ <title>Examples</title>
+
<para>
- Cluster the <literal>employees</literal> relation on the basis of
- its ID attribute:
- </para>
- <programlisting>
+ Cluster the table <literal>employees</literal> on the basis of
+ its index <literal>emp_ind</literal>:
+<programlisting>
CLUSTER emp_ind ON emp;
- </programlisting>
+</programlisting>
+ </para>
+
<para>
Cluster the <literal>employees</literal> relation using the same
index that was used before:
- </para>
- <programlisting>
+<programlisting>
CLUSTER emp;
- </programlisting>
+</programlisting>
+ </para>
+
<para>
Cluster all the tables on the database that have previously been clustered:
- </para>
- <programlisting>
+<programlisting>
CLUSTER;
- </programlisting>
+</programlisting>
+ </para>
</refsect1>
- <refsect1 id="R1-SQL-CLUSTER-3">
- <title>
- Compatibility
- </title>
-
- <refsect2 id="R2-SQL-CLUSTER-4">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- SQL92
- </title>
- <para>
- There is no <command>CLUSTER</command> statement in SQL92.
- </para>
- </refsect2>
+ <refsect1>
+ <title>Compatibility</title>
+
+ <para>
+ There is no <command>CLUSTER</command> statement in the SQL standard.
+ </para>
</refsect1>
<refsect1>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/comment.sgml,v 1.20 2002/07/12 18:43:12 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/comment.sgml,v 1.21 2003/04/15 13:25:08 petere Exp $
PostgreSQL documentation
-->
<refentrytitle id="SQL-COMMENT-TITLE">COMMENT</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
+
<refnamediv>
- <refname>
- COMMENT
- </refname>
- <refpurpose>
- define or change the comment of an object
- </refpurpose>
+ <refname>COMMENT</refname>
+ <refpurpose>define or change the comment of an object</refpurpose>
</refnamediv>
+
<refsynopsisdiv>
- <refsynopsisdivinfo>
- <date>1999-07-20</date>
- </refsynopsisdivinfo>
- <synopsis>
+<synopsis>
COMMENT ON
-[
+{
TABLE <replaceable class="PARAMETER">object_name</replaceable> |
COLUMN <replaceable class="PARAMETER">table_name</replaceable>.<replaceable class="PARAMETER">column_name</replaceable> |
AGGREGATE <replaceable class="PARAMETER">agg_name</replaceable> (<replaceable class="PARAMETER">agg_type</replaceable>) |
TRIGGER <replaceable class="PARAMETER">trigger_name</replaceable> ON <replaceable class="PARAMETER">table_name</replaceable> |
TYPE <replaceable class="PARAMETER">object_name</replaceable> |
VIEW <replaceable class="PARAMETER">object_name</replaceable>
-] IS <replaceable class="PARAMETER">'text'</replaceable>
- </synopsis>
-
- <refsect2 id="R2-SQL-COMMENT-1">
- <refsect2info>
- <date>1999-10-25</date>
- </refsect2info>
- <title>
- Inputs
- </title>
- <para>
-
- <variablelist>
- <varlistentry>
- <term><replaceable class="PARAMETER">object_name,
- table_name.column_name, agg_name, constraint_name, func_name, op, rule_name, trigger_name</replaceable></term>
- <listitem>
- <para>
- The name of the object to be be commented. Names of tables,
- aggregates, domains, functions, indexes, operators, sequences, types,
- and views
- may be schema-qualified.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><replaceable class="PARAMETER">text</replaceable></term>
- <listitem>
- <para>
- The comment to add.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
- </refsect2>
-
- <refsect2 id="R2-SQL-COMMENT-2">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- Outputs
- </title>
- <para>
-
- <variablelist>
- <varlistentry>
- <term><computeroutput>
-COMMENT
- </computeroutput></term>
- <listitem>
- <para>
- Message returned if the table is successfully commented.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
- </refsect2>
+} IS <replaceable class="PARAMETER">'text'</replaceable>
+</synopsis>
</refsynopsisdiv>
- <refsect1 id="R1-SQL-COMMENT-1">
- <refsect1info>
- <date>1998-10-25</date>
- </refsect1info>
- <title>
- Description
- </title>
+ <refsect1>
+ <title>Description</title>
+
<para>
<command>COMMENT</command> stores a comment about a database object.
Comments can be
- easily retrieved with <command>psql</command>'s
- <command>\dd</command>, <command>\d+</command>, or <command>\l+</command>
- commands. Other user interfaces to retrieve comments can be built atop
- the same built-in functions that <command>psql</command> uses, namely
- <function>obj_description()</> and <function>col_description()</>.
+ easily retrieved with the <application>psql</application> commands
+ <command>\dd</command>, <command>\d+</command>, and <command>\l+</command>.
+ Other user interfaces to retrieve comments can be built atop
+ the same built-in functions that <application>psql</application> uses, namely
+ <function>obj_description</> and <function>col_description</>.
</para>
<para>
string.
Comments are automatically dropped when the object is dropped.
</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Parameters</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><replaceable class="parameter">object_name</replaceable></term>
+ <term><replaceable class="parameter">table_name.column_name</replaceable></term>
+ <term><replaceable class="parameter">aggname</replaceable></term>
+ <term><replaceable class="parameter">constraint_name</replaceable></term>
+ <term><replaceable class="parameter">func_name</replaceable></term>
+ <term><replaceable class="parameter">op</replaceable></term>
+ <term><replaceable class="parameter">rule_name</replaceable></term>
+ <term><replaceable class="parameter">trigger_name</replaceable></term>
+ <listitem>
+ <para>
+ The name of the object to be be commented. Names of tables,
+ aggregates, domains, functions, indexes, operators, sequences,
+ types, and views may be schema-qualified.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="parameter">text</replaceable></term>
+ <listitem>
+ <para>
+ The new comment.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Diagnostics</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><computeroutput>COMMENT</computeroutput></term>
+ <listitem>
+ <para>
+ Message returned if the comment was successfully changed.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Notes</title>
- <note>
<para>
- There is presently no security mechanism
- for comments: any user connected to a database can see all the comments
- for objects in that database (although only superusers can change
- comments for objects that they don't own). Therefore, don't put
- security-critical information in comments.
+ There is presently no security mechanism for comments: any user
+ connected to a database can see all the comments for objects in
+ that database (although only superusers can change comments for
+ objects that they don't own). Therefore, don't put
+ security-critical information in comments.
</para>
- </note>
</refsect1>
- <refsect1 id="R1-SQL-COMMENT-2">
- <title>
- Usage
- </title>
+ <refsect1>
+ <title>Examples</title>
+
<para>
Attach a comment to the table <literal>mytable</literal>:
+<programlisting>
COMMENT ON TABLE mytable IS 'This is my table.';
- </programlisting>
+</programlisting>
Remove it again:
+<programlisting>
COMMENT ON TABLE mytable IS NULL;
- </programlisting>
+</programlisting>
</para>
<para>
Some more examples:
+<programlisting>
COMMENT ON AGGREGATE my_aggregate (double precision) IS 'Computes sample variance';
-COMMENT ON COLUMN my_table.my_field IS 'Employee ID number';
+COMMENT ON COLUMN my_table.my_column IS 'Employee ID number';
COMMENT ON DATABASE my_database IS 'Development Database';
COMMENT ON DOMAIN my_domain IS 'Email Address Domain';
COMMENT ON FUNCTION my_function (timestamp) IS 'Returns Roman Numeral';
-COMMENT ON INDEX my_index IS 'Enforces uniqueness on employee id';
+COMMENT ON INDEX my_index IS 'Enforces uniqueness on employee ID';
COMMENT ON OPERATOR ^ (text, text) IS 'Performs intersection of two texts';
COMMENT ON OPERATOR ^ (NONE, text) IS 'This is a prefix operator on text';
-COMMENT ON RULE my_rule ON my_table IS 'Logs UPDATES of employee records';
+COMMENT ON RULE my_rule ON my_table IS 'Logs updates of employee records';
COMMENT ON SCHEMA my_schema IS 'Departmental data';
COMMENT ON SEQUENCE my_sequence IS 'Used to generate primary keys';
COMMENT ON TABLE my_schema.my_table IS 'Employee Information';
-COMMENT ON TRIGGER my_trigger ON my_table IS 'Used for R.I.';
-COMMENT ON TYPE complex IS 'Complex Number datatype';
+COMMENT ON TRIGGER my_trigger ON my_table IS 'Used for RI';
+COMMENT ON TYPE complex IS 'Complex number data type';
COMMENT ON VIEW my_view IS 'View of departmental costs';
- </programlisting>
+</programlisting>
</para>
</refsect1>
- <refsect1 id="R1-SQL-COMMENT-3">
- <title>
- Compatibility
- </title>
-
- <refsect2 id="R2-SQL-COMMENT-4">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- SQL92
- </title>
- <para>
- There is no <command>COMMENT</command> in <acronym>SQL92</acronym>.
- </para>
- </refsect2>
+ <refsect1>
+ <title>Compatibility</title>
+
+ <para>
+ There is no <command>COMMENT</command> command in the SQL standard.
+ </para>
</refsect1>
</refentry>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/commit.sgml,v 1.14 2002/04/21 19:02:39 thomas Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/commit.sgml,v 1.15 2003/04/15 13:25:08 petere Exp $
PostgreSQL documentation
-->
<refentrytitle id="SQL-COMMIT-TITLE">COMMIT</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
+
<refnamediv>
- <refname>
- COMMIT
- </refname>
- <refpurpose>
- commit the current transaction
- </refpurpose>
+ <refname>COMMIT</refname>
+ <refpurpose>commit the current transaction</refpurpose>
</refnamediv>
<refsynopsisdiv>
- <refsynopsisdivinfo>
- <date>1999-07-20</date>
- </refsynopsisdivinfo>
- <synopsis>
+<synopsis>
COMMIT [ WORK | TRANSACTION ]
- </synopsis>
-
- <refsect2 id="R2-SQL-COMMIT-1">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- Inputs
- </title>
- <para>
-
- <variablelist>
- <varlistentry>
- <term>WORK</term>
- <term>TRANSACTION</term>
- <listitem>
- <para>
- Optional keywords. They have no effect.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
- </refsect2>
-
- <refsect2 id="R2-SQL-COMMIT-2">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- Outputs
- </title>
- <para>
-
- <variablelist>
- <varlistentry>
- <term><computeroutput>
-COMMIT
- </computeroutput></term>
- <listitem>
- <para>
- Message returned if the transaction is successfully committed.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><computeroutput>
-WARNING: COMMIT: no transaction in progress
- </computeroutput></term>
- <listitem>
- <para>
- If there is no transaction in progress.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
- </refsect2>
+</synopsis>
</refsynopsisdiv>
- <refsect1 id="R1-SQL-COMMIT-1">
- <refsect1info>
- <date>1998-09-08</date>
- </refsect1info>
- <title>
- Description
- </title>
+ <refsect1>
+ <title>Description</title>
+
<para>
<command>COMMIT</command> commits the current transaction. All
changes made by the transaction become visible to others
and are guaranteed to be durable if a crash occurs.
</para>
+ </refsect1>
- <refsect2 id="R2-SQL-COMMIT-3">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- Notes
- </title>
- <para>
- The keywords WORK and TRANSACTION are noise and can be omitted.
- </para>
+ <refsect1>
+ <title>Parameters</title>
- <para>
- Use <xref linkend="SQL-ROLLBACK" endterm="SQL-ROLLBACK-TITLE">
- to abort a transaction.
- </para>
- </refsect2>
+ <variablelist>
+ <varlistentry>
+ <term><literal>WORK</literal></term>
+ <term><literal>TRANSACTION</literal></term>
+ <listitem>
+ <para>
+ Optional key words. They have no effect.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
</refsect1>
+
+ <refsect1>
+ <title>Diagnostics</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><computeroutput>COMMIT</computeroutput></term>
+ <listitem>
+ <para>
+ Message returned if the transaction was successfully committed.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><computeroutput>WARNING: COMMIT: no transaction in progress</computeroutput></term>
+ <listitem>
+ <para>
+ Message if there is no transaction in progress.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Notes</title>
- <refsect1 id="R1-SQL-COMMIT-2">
- <title>
- Usage
- </title>
<para>
- To make all changes permanent:
- <programlisting>
-COMMIT WORK;
- </programlisting>
+ Use <xref linkend="SQL-ROLLBACK" endterm="SQL-ROLLBACK-TITLE"> to
+ abort a transaction.
+ </para>
+ </refsect1>
+
+ <refsect1>
+ <title>Examples</title>
+
+ <para>
+ To commit the current transaction and make all changes permanent:
+<programlisting>
+COMMIT;
+</programlisting>
</para>
</refsect1>
- <refsect1 id="R1-SQL-COMMIT-3">
- <title>
- Compatibility
- </title>
+ <refsect1>
+ <title>Compatibility</title>
- <refsect2 id="R2-SQL-COMMIT-4">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- SQL92
- </title>
- <para>
- <acronym>SQL92</acronym> only specifies the two forms <literal>COMMIT</literal>
- and <literal>COMMIT WORK</literal>. Otherwise full compatibility.
- </para>
- </refsect2>
+ <para>
+ The SQL standard only specifies the two forms
+ <literal>COMMIT</literal> and <literal>COMMIT
+ WORK</literal>. Otherwise, this command is fully conforming.
+ </para>
</refsect1>
</refentry>
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/copy.sgml,v 1.41 2003/03/27 16:51:27 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/copy.sgml,v 1.42 2003/04/15 13:25:08 petere Exp $
PostgreSQL documentation
-->
<refentrytitle id="sql-copy-title">COPY</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
+
<refnamediv>
- <refname>
- COPY
- </refname>
- <refpurpose>
- copy data between files and tables
- </refpurpose>
+ <refname>COPY</refname>
+ <refpurpose>copy data between files and tables</refpurpose>
</refnamediv>
+
<refsynopsisdiv>
- <refsynopsisdivinfo>
- <date>1999-12-11</date>
- </refsynopsisdivinfo>
- <synopsis>
+<synopsis>
COPY <replaceable class="parameter">table</replaceable> [ ( <replaceable class="parameter">column</replaceable> [, ...] ) ]
- FROM { '<replaceable class="parameter">filename</replaceable>' | <filename>stdin</filename> }
+ FROM { '<replaceable class="parameter">filename</replaceable>' | STDIN }
[ [ WITH ]
[ BINARY ]
[ OIDS ]
[ DELIMITER [ AS ] '<replaceable class="parameter">delimiter</replaceable>' ]
[ NULL [ AS ] '<replaceable class="parameter">null string</replaceable>' ] ]
+
COPY <replaceable class="parameter">table</replaceable> [ ( <replaceable class="parameter">column</replaceable> [, ...] ) ]
- TO { '<replaceable class="parameter">filename</replaceable>' | <filename>stdout</filename> }
+ TO { '<replaceable class="parameter">filename</replaceable>' | STDOUT }
[ [ WITH ]
[ BINARY ]
[ OIDS ]
[ DELIMITER [ AS ] '<replaceable class="parameter">delimiter</replaceable>' ]
[ NULL [ AS ] '<replaceable class="parameter">null string</replaceable>' ] ]
- </synopsis>
-
- <refsect2 id="R2-SQL-COPY-1">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- Inputs
- </title>
- <para>
-
- <variablelist>
- <varlistentry>
- <term><replaceable class="parameter">table</replaceable></term>
- <listitem>
- <para>
- The name (possibly schema-qualified) of an existing table.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><replaceable class="parameter">column</replaceable></term>
- <listitem>
- <para>
- An optional list of columns to be copied. If no column list is
- specified, all columns will be used.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><replaceable class="parameter">filename</replaceable></term>
- <listitem>
- <para>
- The absolute Unix path name of the input or output file.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><filename>stdin</filename></term>
- <listitem>
- <para>
- Specifies that input comes from the client application.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><filename>stdout</filename></term>
- <listitem>
- <para>
- Specifies that output goes to the client application.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term>BINARY</term>
- <listitem>
- <para>
- Changes the behavior of field formatting, forcing all data to be
- stored or read in binary format rather than as text. You can not
- specify <option>DELIMITER</option> or <option>NULL</option>
- in binary mode.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term>OIDS</term>
- <listitem>
- <para>
- Specifies copying the internal object id (OID) for each row.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><replaceable class="parameter">delimiter</replaceable></term>
- <listitem>
- <para>
- The single character that separates fields within each row (line) of the file.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><replaceable class="parameter">null string</replaceable></term>
- <listitem>
- <para>
- The string that represents a NULL value. The default is
- <quote><literal>\N</literal></quote> (backslash-N). You might
- prefer an empty string, for example.
- </para>
- <note>
- <para>
- On a <command>COPY FROM</command>, any data item that matches
- this string will be stored as a NULL value, so you should
- make sure that you use the same string as you used with
- <command>COPY TO</command>.
- </para>
- </note>
- </listitem>
- </varlistentry>
-
- </variablelist>
- </para>
- </refsect2>
-
- <refsect2 id="R2-SQL-COPY-2">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- Outputs
- </title>
- <para>
-
- <variablelist>
- <varlistentry>
- <term><computeroutput>
-COPY
- </computeroutput></term>
- <listitem>
- <para>
- The copy completed successfully.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><computeroutput>
-ERROR: <replaceable>reason</replaceable>
- </computeroutput></term>
- <listitem>
- <para>
- The copy failed for the reason stated in the error message.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
- </refsect2>
+</synopsis>
</refsynopsisdiv>
- <refsect1 id="R1-SQL-COPY-1">
- <refsect1info>
- <date>2001-01-02</date>
- </refsect1info>
- <title>
- Description
- </title>
+ <refsect1>
+ <title>Description</title>
+
<para>
<command>COPY</command> moves data between
<productname>PostgreSQL</productname> tables and standard file-system
<para>
<command>COPY</command> with a file name instructs the
- <productname>PostgreSQL</productname> backend to directly read from
- or write to a file. The file must be accessible to the backend and
- the name must be specified from the viewpoint of the backend. When
- <filename>stdin</filename> or <filename>stdout</filename> is
+ <productname>PostgreSQL</productname> server to directly read from
+ or write to a file. The file must be accessible to the server and
+ the name must be specified from the viewpoint of the server. When
+ <literal>STDIN</literal> or <literal>STDOUT</literal> is
specified, data is transmitted via the connection between the
- client frontend and the backend.
-
- <tip>
+ client and the server.
+ </para>
+ </refsect1>
+
+ <refsect1>
+ <title>Parameters</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><replaceable class="parameter">table</replaceable></term>
+ <listitem>
<para>
- Do not confuse <command>COPY</command> with the
- <application>psql</application> instruction
- <command>\copy</command>. <command>\copy</command> invokes
- <command>COPY FROM stdin</command> or <command>COPY TO
- stdout</command>, and then fetches/stores the data in a file
- accessible to the <application>psql</application> client. Thus,
- file accessibility and access rights depend on the client rather
- than the backend when <command>\copy</command> is used.
+ The name (possibly schema-qualified) of an existing table.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="parameter">column</replaceable></term>
+ <listitem>
+ <para>
+ An optional list of columns to be copied. If no column list is
+ specified, all columns will be used.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="parameter">filename</replaceable></term>
+ <listitem>
+ <para>
+ The absolute path name of the input or output file.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>STDIN</literal></term>
+ <listitem>
+ <para>
+ Specifies that input comes from the client application.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>STDOUT</literal></term>
+ <listitem>
+ <para>
+ Specifies that output goes to the client application.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>BINARY</literal></term>
+ <listitem>
+ <para>
+ Forces all data to be stored or read in binary format rather
+ than as text. You cannot specify the <option>DELIMITER</option>
+ or <option>NULL</option> options in binary mode.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>OIDS</literal></term>
+ <listitem>
+ <para>
+ Specifies copying the OID for each row. (An error is raised if
+ <literal>OIDS</literal> is specified for a table that does not
+ have OIDs.)
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="parameter">delimiter</replaceable></term>
+ <listitem>
+ <para>
+ The single character that separates columns within each row
+ (line) of the file. The default is a tab character.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="parameter">null string</replaceable></term>
+ <listitem>
+ <para>
+ The string that represents a null value. The default is
+ <literal>\N</literal> (backslash-N). You might prefer an empty
+ string, for example.
</para>
- </tip>
- </para>
- <refsect2 id="R2-SQL-COPY-3">
- <refsect2info>
- <date>2001-01-02</date>
- </refsect2info>
- <title>
- Notes
- </title>
+ <note>
+ <para>
+ On a <command>COPY FROM</command>, any data item that matches
+ this string will be stored as a null value, so you should make
+ sure that you use the same string as you used with
+ <command>COPY TO</command>.
+ </para>
+ </note>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Diagnostics</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><computeroutput>COPY</computeroutput></term>
+ <listitem>
+ <para>
+ The copy operation completed successfully.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Notes</title>
+
<para>
<command>COPY</command> can only be used with plain tables, not
with views.
</para>
<para>
- The BINARY keyword will force all data to be
+ The <literal>BINARY</literal> key word will force all data to be
stored/read as binary format rather than as text. It is
- somewhat faster than the normal copy command, but a binary copy
+ somewhat faster than the normal text mode, but a binary format
file is not portable across machine architectures.
- </para>
-
- <para>
- By default, a text copy uses a tab ("\t") character as a delimiter
- between fields. The field delimiter may be changed to any other
- single character with the keyword <option>DELIMITER</option>. Characters
- in data fields that happen to match the delimiter character will be
- backslash quoted.
- </para>
-
- <para>
- You must have <firstterm>select privilege</firstterm> on any table
- whose values are read by <command>COPY TO</command>, and
- <firstterm>insert privilege</firstterm> on a table into which values
- are being inserted by <command>COPY FROM</command>. The backend also
- needs appropriate Unix permissions for any file read or written by
- <command>COPY</command>.
- </para>
-
- <para>
- <command>COPY FROM</command> will invoke any triggers and check
- constraints on the destination table. However, it will not invoke rules.
</para>
<para>
- <command>COPY</command> stops operation at the first error. This
- should not lead to problems in the event of a <command>COPY
- TO</command>, but the target relation will already have received
- earlier rows in a <command>COPY FROM</command>. These rows will not
- be visible or accessible, but they still occupy disk space. This may
- amount to a considerable amount of wasted disk space if the failure
- happened well into a large copy operation. You may wish to invoke
- <command>VACUUM</command> to recover the wasted space.
+ You must have select privilege on any table
+ whose values are read by <command>COPY TO</command>, and
+ insert privilege on a table into which values
+ are being inserted by <command>COPY FROM</command>.
</para>
<para>
Files named in a <command>COPY</command> command are read or written
- directly by the backend, not by the client application. Therefore,
+ directly by the server, not by the client application. Therefore,
they must reside on or be accessible to the database server machine,
not the client. They must be accessible to and readable or writable
by the <application>PostgreSQL</application> user (the user ID the
server runs as), not the client. <command>COPY</command> naming a
file is only allowed to database superusers, since it allows reading
- or writing any file that the backend has privileges to access.
-
- <tip>
- <para>
- The
- <application>psql</application> instruction <command>\copy</command>
- reads or writes files on the client machine with the client's
- permissions, so it is not restricted to superusers.
- </para>
- </tip>
+ or writing any file that the server has privileges to access.
+ </para>
+
+ <para>
+ Do not confuse <command>COPY</command> with the
+ <application>psql</application> instruction
+ <command>\copy</command>. <command>\copy</command> invokes
+ <command>COPY FROM STDIN</command> or <command>COPY TO
+ STDOUT</command>, and then fetches/stores the data in a file
+ accessible to the <application>psql</application> client. Thus,
+ file accessibility and access rights depend on the client rather
+ than the server when <command>\copy</command> is used.
</para>
<para>
It is recommended that the file name used in <command>COPY</command>
always be specified as an absolute path. This is enforced by the
- backend in the case of <command>COPY TO</command>, but for
+ server in the case of <command>COPY TO</command>, but for
<command>COPY FROM</command> you do have the option of reading from
a file specified by a relative path. The path will be interpreted
- relative to the backend's working directory (somewhere below
- <filename>$PGDATA</filename>), not the client's working directory.
+ relative to the working directory of the server process (somewhere below
+ the data directory), not the client's working directory.
+ </para>
+
+ <para>
+ <command>COPY FROM</command> will invoke any triggers and check
+ constraints on the destination table. However, it will not invoke rules.
+ </para>
+
+ <para>
+ <command>COPY</command> stops operation at the first error. This
+ should not lead to problems in the event of a <command>COPY
+ TO</command>, but the target table will already have received
+ earlier rows in a <command>COPY FROM</command>. These rows will not
+ be visible or accessible, but they still occupy disk space. This may
+ amount to a considerable amount of wasted disk space if the failure
+ happened well into a large copy operation. You may wish to invoke
+ <command>VACUUM</command> to recover the wasted space.
</para>
- </refsect2>
</refsect1>
- <refsect1 id="R1-SQL-COPY-2">
- <refsect1info>
- <date>2001-01-02</date>
- </refsect1info>
+ <refsect1>
<title>File Formats</title>
+
<refsect2>
- <refsect2info>
- <date>2002-02-12</date>
- </refsect2info>
<title>Text Format</title>
+
<para>
- When <command>COPY</command> is used without the BINARY option,
- the file read or written is a text file with one line per table row.
- Columns (attributes) in a row are separated by the delimiter character.
- The attribute values themselves are strings generated by the
+ When <command>COPY</command> is used without the <literal>BINARY</literal> option,
+ the data read or written is a text file with one line per table row.
+ Columns in a row are separated by the delimiter character.
+ The column values themselves are strings generated by the
output function, or acceptable to the input function, of each
attribute's data type. The specified null-value string is used in
- place of attributes that are NULL.
+ place of columns that are null.
<command>COPY FROM</command> will raise an error if any line of the
input file contains more or fewer columns than are expected.
+ If <literal>OIDS</literal> is specified, the OID is read or written as the first column,
+ preceding the user data columns.
</para>
- <para>
- If OIDS is specified, the OID is read or written as the first column,
- preceding the user data columns. (An error is raised if OIDS is
- specified for a table that does not have OIDs.)
- </para>
+
<para>
End of data can be represented by a single line containing just
backslash-period (<literal>\.</>). An end-of-data marker is
- not necessary when reading from a Unix file, since the end of file
+ not necessary when reading from a file, since the end of file
serves perfectly well; but an end marker must be provided when copying
data to or from a client application.
</para>
+
<para>
Backslash characters (<literal>\</>) may be used in the
<command>COPY</command> data to quote data characters that might
otherwise be taken as row or column delimiters. In particular, the
following characters <emphasis>must</> be preceded by a backslash if
- they appear as part of an attribute value: backslash itself,
+ they appear as part of a column value: backslash itself,
newline, and the current delimiter character.
</para>
+
<para>
The following special backslash sequences are recognized by
<command>COPY FROM</command>:
backslash sequence, but it does use the other sequences listed above
for those control characters.
</para>
+
<para>
Never put a backslash before a data character <literal>N</> or period
(<literal>.</>). Such pairs will be mistaken for the default null string
or the end-of-data marker, respectively. Any other backslashed character
that is not mentioned in the above table will be taken to represent itself.
</para>
+
<para>
It is strongly recommended that applications generating COPY data convert
data newlines and carriage returns to the <literal>\n</> and
- <literal>\r</> sequences respectively. At present
- (<productname>PostgreSQL</productname> 7.2 and older versions) it is
+ <literal>\r</> sequences respectively. At present it is
possible to represent a data carriage return without any special quoting,
and to represent a data newline by a backslash and newline. However,
these representations will not be accepted by default in future releases.
</para>
+
<para>
Note that the end of each row is marked by a Unix-style newline
- ("\n"). Presently, <command>COPY FROM</command> will not behave as
+ (<quote><literal>\n</></>). Presently, <command>COPY FROM</command> will not behave as
desired if given a file containing DOS- or Mac-style newlines.
This is expected to change in future releases.
</para>
</refsect2>
<refsect2>
- <refsect2info>
- <date>2001-01-02</date>
- </refsect2info>
<title>Binary Format</title>
+
<para>
The file format used for <command>COPY BINARY</command> changed in
- <application>PostgreSQL</application> v7.1. The new format consists
- of a file header, zero or more tuples, and a file trailer.
+ <application>PostgreSQL</application> 7.1. The new format consists
+ of a file header, zero or more tuples containing the row data, and
+ a file trailer.
</para>
<refsect3>
- <refsect3info>
- <date>2001-01-02</date>
- </refsect3info>
- <title>
- File Header
- </title>
+ <title>File Header</title>
+
<para>
The file header consists of 24 bytes of fixed fields, followed
by a variable-length header extension area. The fixed fields are:
<term>Signature</term>
<listitem>
<para>
-12-byte sequence <literal>PGBCOPY\n\377\r\n\0</> --- note that the null
+12-byte sequence <literal>PGBCOPY\n\377\r\n\0</> --- note that the zero byte
is a required part of the signature. (The signature is designed to allow
easy identification of files that have been munged by a non-8-bit-clean
transfer. This signature will be changed by newline-translation
-filters, dropped nulls, dropped high bits, or parity changes.)
+filters, dropped zero bytes, dropped high bits, or parity changes.)
</para>
</listitem>
</varlistentry>
<term>Integer layout field</term>
<listitem>
<para>
-int32 constant 0x01020304 in source's byte order. Potentially, a reader
+32-bit integer constant 0x01020304 in source's byte order. Potentially, a reader
could engage in byte-flipping of subsequent fields if the wrong byte
order is detected here.
</para>
<term>Flags field</term>
<listitem>
<para>
-int32 bit mask to denote important aspects of the file format. Bits are
+32-bit integer bit mask to denote important aspects of the file format. Bits are
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
<term>Bit 16</term>
<listitem>
<para>
- if 1, OIDs are included in the dump; if 0, not
+ if 1, OIDs are included in the data; if 0, not
</para>
</listitem>
</varlistentry>
<term>Header extension area length</term>
<listitem>
<para>
-int32 length in bytes of remainder of header, not including self. In
-the initial version this will be zero, and the first tuple follows
+32-bit integer, length in bytes of remainder of header, not including self.
+Currently, this is zero, and the first tuple follows
immediately. Future changes to the format might allow additional data
to be present in the header. A reader should silently skip over any header
extension data it does not know what to do with.
</refsect3>
<refsect3>
- <refsect3info>
- <date>2001-01-02</date>
- </refsect3info>
- <title>
- Tuples
- </title>
+ <title>Tuples</title>
<para>
-Each tuple begins with an int16 count of the number of fields in the
+Each tuple begins with a 16-bit integer 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 <structfield>typlen</> word possibly followed by field data.
+tuple, there is a 16-bit integer <structfield>typlen</> word possibly followed by field data.
The <structfield>typlen</> field is interpreted thus:
<variablelist>
<term>Zero</term>
<listitem>
<para>
- Field is NULL. No data follows.
+ Field is null. No data follows.
</para>
</listitem>
</varlistentry>
<term>> 0</term>
<listitem>
<para>
- Field is a fixed-length data type. Exactly N
+ Field is a fixed-length data type. Exactly that many
bytes of data follow the <structfield>typlen</> word.
</para>
</listitem>
<para>
Field is a <literal>varlena</> data type. The next four
bytes are the <literal>varlena</> header, which contains
- the total value length including itself.
+ the total value length including the header itself.
</para>
</listitem>
</varlistentry>
</para>
<para>
-For non-NULL fields, the reader can check that the <structfield>typlen</> matches the
+For nonnull 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>
<para>
-If OIDs are included in the dump, the OID field immediately follows the
+If OIDs are included in the file, 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 <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.
+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>
</refsect3>
<refsect3>
- <refsect3info>
- <date>2001-01-02</date>
- </refsect3info>
- <title>
- File Trailer
- </title>
+ <title>File Trailer</title>
+
<para>
- The file trailer consists of an int16 word containing -1. This is
+ The file trailer consists of an 16-bit integer word containing -1. This is
easily distinguished from a tuple's field-count word.
</para>
</refsect2>
</refsect1>
- <refsect1 id="R1-SQL-COPY-3">
- <title>
- Usage
- </title>
+ <refsect1>
+ <title>Examples</title>
+
<para>
- The following example copies a table to standard output,
- using a vertical bar (|) as the field delimiter:
+ The following example copies a table to the client
+ using the vertical bar (<literal>|</literal>) as the field delimiter:
+<programlisting>
+COPY country TO STDOUT WITH DELIMITER '|';
+</programlisting>
</para>
- <programlisting>
-COPY country TO <filename>stdout</filename> WITH DELIMITER '|';
- </programlisting>
+
<para>
- To copy data from a Unix file into the <literal>country</> table:
- </para>
- <programlisting>
+ To copy data from a file into the <literal>country</> table:
+<programlisting>
COPY country FROM '/usr1/proj/bray/sql/country_data';
- </programlisting>
+</programlisting>
+ </para>
+
<para>
Here is a sample of data suitable for copying into a table from
- <filename>stdin</filename> (so it has the termination sequence on the
+ <literal>STDIN</literal> (so it must have the termination sequence on the
last line):
- </para>
- <programlisting>
+<programlisting>
AF AFGHANISTAN
AL ALBANIA
DZ ALGERIA
ZM ZAMBIA
ZW ZIMBABWE
\.
- </programlisting>
- <para>
- Note that the white space on each line is actually a TAB.
+</programlisting>
+ Note that the white space on each line is actually a tab character.
</para>
+
<para>
The following is the same data, output in binary format on a
Linux/i586 machine. The data is shown after filtering through the
- Unix utility <command>od -c</command>. The table has three fields;
- the first is <type>char(2)</type>, the second is <type>text</type>,
- and the third is <type>integer</type>. All the rows have a null value
- in the third field.
- </para>
- <programlisting>
+ Unix utility <command>od -c</command>. The table has three columns;
+ the first has type <type>char(2)</type>, the second has type <type>text</type>,
+ and the third has type <type>integer</type>. All the rows have a null value
+ in the third column.
+<programlisting>
0000000 P G B C O P Y \n 377 \r \n \0 004 003 002 001
0000020 \0 \0 \0 \0 \0 \0 \0 \0 003 \0 377 377 006 \0 \0 \0
0000040 A F 377 377 017 \0 \0 \0 A F G H A N I S
0000160 M 377 377 \n \0 \0 \0 Z A M B I A \0 \0 003
0000200 \0 377 377 006 \0 \0 \0 Z W 377 377 \f \0 \0 \0 Z
0000220 I M B A B W E \0 \0 377 377
- </programlisting>
+</programlisting>
+ </para>
</refsect1>
- <refsect1 id="R1-SQL-COPY-6">
- <title>
- Compatibility
- </title>
+ <refsect1>
+ <title>Compatibility</title>
- <refsect2 id="R2-SQL-COPY-4">
- <refsect2info>
- <date>1998-09-08</date>
- </refsect2info>
- <title>
- SQL92
- </title>
- <para>
- There is no <command>COPY</command> statement in SQL92.
- </para>
- <para>
- The following syntax was used by pre-7.3 applications and is still supported:
- <synopsis>
- COPY [ BINARY ] <replaceable class="parameter">table</replaceable> [ WITH OIDS ]
- FROM { '<replaceable class="parameter">filename</replaceable>' | <filename>stdin</filename> }
- [ [USING] DELIMITERS '<replaceable class="parameter">delimiter</replaceable>' ]
- [ WITH NULL AS '<replaceable class="parameter">null string</replaceable>' ]
- COPY [ BINARY ] <replaceable class="parameter">table</replaceable> [ WITH OIDS ]
- TO { '<replaceable class="parameter">filename</replaceable>' | <filename>stdout</filename> }
- [ [USING] DELIMITERS '<replaceable class="parameter">delimiter</replaceable>' ]
- [ WITH NULL AS '<replaceable class="parameter">null string</replaceable>' ]
- </synopsis>
- </para>
- </refsect2>
+ <para>
+ There is no <command>COPY</command> statement in the SQL standard.
+ </para>
+
+ <para>
+ The following syntax was used before PostgreSQL version 7.3 and is
+ still supported:
+
+<synopsis>
+COPY [ BINARY ] <replaceable class="parameter">table</replaceable> [ WITH OIDS ]
+ FROM { '<replaceable class="parameter">filename</replaceable>' | STDIN }
+ [ [USING] DELIMITERS '<replaceable class="parameter">delimiter</replaceable>' ]
+ [ WITH NULL AS '<replaceable class="parameter">null string</replaceable>' ]
+
+COPY [ BINARY ] <replaceable class="parameter">table</replaceable> [ WITH OIDS ]
+ TO { '<replaceable class="parameter">filename</replaceable>' | STDOUT }
+ [ [USING] DELIMITERS '<replaceable class="parameter">delimiter</replaceable>' ]
+ [ WITH NULL AS '<replaceable class="parameter">null string</replaceable>' ]
+</synopsis>
+ </para>
</refsect1>
</refentry>
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