mirror of
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Last round of reference page editing.
This commit is contained in:
Peter Eisentraut
@@ -1,5 +1,5 @@
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<!--
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$Header: /cvsroot/pgsql/doc/src/sgml/ref/set.sgml,v 1.74 2003/04/25 19:45:08 tgl Exp $
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$Header: /cvsroot/pgsql/doc/src/sgml/ref/set.sgml,v 1.75 2003/05/04 02:23:16 petere Exp $
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||||
PostgreSQL documentation
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||||
-->
|
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|
||||
@@ -8,73 +8,20 @@ PostgreSQL documentation
|
||||
<refentrytitle id="SQL-SET-TITLE">SET</refentrytitle>
|
||||
<refmiscinfo>SQL - Language Statements</refmiscinfo>
|
||||
</refmeta>
|
||||
|
||||
<refnamediv>
|
||||
<refname>SET</refname>
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||||
<refpurpose>change a run-time parameter</refpurpose>
|
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</refnamediv>
|
||||
|
||||
<refsynopsisdiv>
|
||||
<synopsis>
|
||||
<synopsis>
|
||||
SET [ SESSION | LOCAL ] <replaceable class="PARAMETER">variable</replaceable> { TO | = } { <replaceable class="PARAMETER">value</replaceable> | '<replaceable class="PARAMETER">value</replaceable>' | DEFAULT }
|
||||
SET [ SESSION | LOCAL ] TIME ZONE { <replaceable class="PARAMETER">timezone</replaceable> | LOCAL | DEFAULT }
|
||||
</synopsis>
|
||||
|
||||
<refsect2 id="R2-SQL-SET-1">
|
||||
<title>Inputs</title>
|
||||
<para>
|
||||
<variablelist>
|
||||
|
||||
<varlistentry>
|
||||
<term><option>SESSION</></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Specifies that the command takes effect for the current session.
|
||||
(This is the default if neither <option>SESSION</> nor
|
||||
<option>LOCAL</> appears.)
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><option>LOCAL</></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Specifies that the command takes effect for only the current
|
||||
transaction. After <command>COMMIT</> or <command>ROLLBACK</>,
|
||||
the session-level setting takes effect again. Note that
|
||||
<command>SET LOCAL</> will appear to have no effect if it's
|
||||
executed outside a <command>BEGIN</> block, since the transaction
|
||||
will end immediately.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><replaceable class="PARAMETER">variable</replaceable></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Name of a settable run-time parameter.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><replaceable class="PARAMETER">value</replaceable></term>
|
||||
<listitem>
|
||||
<para>
|
||||
New value of parameter. <option>DEFAULT</option> can be
|
||||
used to specify resetting the parameter to its default
|
||||
value. Lists of strings are allowed, but more complex
|
||||
constructs may need to be single or double quoted.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
</variablelist>
|
||||
</para>
|
||||
</refsect2>
|
||||
|
||||
</synopsis>
|
||||
</refsynopsisdiv>
|
||||
|
||||
<refsect1 id="R1-SQL-SET-1">
|
||||
<refsect1>
|
||||
<title>Description</title>
|
||||
|
||||
<para>
|
||||
@@ -83,7 +30,7 @@ SET [ SESSION | LOCAL ] TIME ZONE { <replaceable class="PARAMETER">timezone</rep
|
||||
<xref linkend="runtime-config"> can be changed on-the-fly with
|
||||
<command>SET</command>.
|
||||
(But some require superuser privileges to change, and others cannot
|
||||
be changed after server or session start.) Note that
|
||||
be changed after server or session start.)
|
||||
<command>SET</command> only affects the value used by the current
|
||||
session.
|
||||
</para>
|
||||
@@ -114,236 +61,153 @@ SET [ SESSION | LOCAL ] TIME ZONE { <replaceable class="PARAMETER">timezone</rep
|
||||
does not start a new transaction block. See the
|
||||
<varname>autocommit</> section in <xref linkend="runtime-config"> for details.
|
||||
</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
<title>Parameters</title>
|
||||
|
||||
<variablelist>
|
||||
<varlistentry>
|
||||
<term><literal>SESSION</></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Specifies that the command takes effect for the current session.
|
||||
(This is the default if neither <literal>SESSION</> nor
|
||||
<literal>LOCAL</> appears.)
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><literal>LOCAL</></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Specifies that the command takes effect for only the current
|
||||
transaction. After <command>COMMIT</> or <command>ROLLBACK</>,
|
||||
the session-level setting takes effect again. Note that
|
||||
<command>SET LOCAL</> will appear to have no effect if it is
|
||||
executed outside a <command>BEGIN</> block, since the
|
||||
transaction will end immediately.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><replaceable class="PARAMETER">variable</replaceable></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Name of a settable run-time parameter. Available parameters are
|
||||
documented in <xref linkend="runtime-config"> and below.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><replaceable class="PARAMETER">value</replaceable></term>
|
||||
<listitem>
|
||||
<para>
|
||||
New value of parameter. Values can be specified as string
|
||||
constants, identifiers, numbers, or comma-separated lists of
|
||||
these. <literal>DEFAULT</literal> can be used to specify
|
||||
resetting the parameter to its default value.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
</variablelist>
|
||||
|
||||
<para>
|
||||
Here are additional details about a few of the parameters that can be set:
|
||||
Besides the configuration parameters documented in <xref
|
||||
linkend="runtime-config">, there are a few that can only be
|
||||
adjusted using the <command>SET</command> command or that have a
|
||||
special syntax:
|
||||
|
||||
<variablelist>
|
||||
<varlistentry>
|
||||
<term><varname>DATESTYLE</></term>
|
||||
<term><literal>NAMES</literal></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Choose the date/time representation style. Two separate
|
||||
settings are involved: the default date/time output format and the
|
||||
interpretation of ambiguous input.
|
||||
<literal>>SET NAMES <replaceable>value</></> is an alias for
|
||||
<literal>SET client_encoding TO <replaceable>value</></>.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
The following are date/time output styles:
|
||||
|
||||
<variablelist>
|
||||
<varlistentry>
|
||||
<term><literal>ISO</></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Use ISO 8601-style dates and times (<literal>YYYY-MM-DD
|
||||
HH:MM:SS</literal>). This is the default.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><literal>SQL</></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Use Oracle/Ingres-style dates and times. Note that this
|
||||
style has nothing to do with SQL (which mandates ISO 8601
|
||||
style); the naming of this option is a historical accident.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><literal>PostgreSQL</></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Use traditional <productname>PostgreSQL</productname> format.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><literal>German</></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Use <literal>dd.mm.yyyy</literal> for numeric date representations.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
</variablelist>
|
||||
</para>
|
||||
|
||||
<para>
|
||||
The following two options determine both a substyle of the
|
||||
<quote>SQL</quote> and <quote>PostgreSQL</quote> output formats
|
||||
and the preferred interpretation of ambiguous date input.
|
||||
|
||||
<variablelist>
|
||||
<varlistentry>
|
||||
<term><literal>European</></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Use <literal>dd/mm/yyyy</literal> for numeric date representations.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><literal>NonEuropean</></term>
|
||||
<term><literal>US</></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Use <literal>mm/dd/yyyy</literal> for numeric date representations.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
</variablelist>
|
||||
</para>
|
||||
|
||||
<para>
|
||||
A value for <command>SET DATESTYLE</command> can be one from
|
||||
the first list (output styles), or one from the second list
|
||||
(substyles), or one from each separated by a comma.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
<command>SET DATESTYLE</command> affects interpretation of
|
||||
input and provides several standard output formats. For
|
||||
applications needing different variations or tighter control
|
||||
over input or output, consider using
|
||||
the <function>to_char</function> family of
|
||||
functions.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
There are several now-deprecated means for setting the date style
|
||||
in addition to the normal methods of setting it via <command>SET</> or
|
||||
a configuration-file entry:
|
||||
<simplelist>
|
||||
<member>
|
||||
Setting the postmaster's <envar>PGDATESTYLE</envar> environment
|
||||
variable. (This will be overridden by any of the other methods.)
|
||||
</member>
|
||||
<member>
|
||||
Running postmaster using the option <option>-o -e</option> to
|
||||
set dates to the <literal>European</literal> convention.
|
||||
(This overrides environment variables and configuration-file
|
||||
entries.)
|
||||
</member>
|
||||
<member>
|
||||
Setting the client's <envar>PGDATESTYLE</envar> environment variable.
|
||||
If <envar>PGDATESTYLE</envar> is set in the frontend environment of a client
|
||||
based on <application>libpq</>, <application>libpq</> will automatically set <varname>DATESTYLE</> to the
|
||||
value of <envar>PGDATESTYLE</envar> during connection start-up. This is
|
||||
equivalent to a manually issued <command>SET DATESTYLE</>.
|
||||
</member>
|
||||
</simplelist>
|
||||
</para>
|
||||
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term>NAMES</term>
|
||||
<term><literal>SEED</literal></term>
|
||||
<listitem>
|
||||
<para>
|
||||
<command>SET NAMES</> is an alias for <command>SET CLIENT_ENCODING</>.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term>SEED</term>
|
||||
<listitem>
|
||||
<para>
|
||||
Sets the internal seed for the random number generator.
|
||||
|
||||
<variablelist>
|
||||
<varlistentry>
|
||||
<term><replaceable class="parameter">value</replaceable></term>
|
||||
<listitem>
|
||||
<para>
|
||||
The value for the seed to be used by the
|
||||
<function>random</function> function. Allowed
|
||||
values are floating-point numbers between 0 and 1, which
|
||||
are then multiplied by 2<superscript>31</>-1.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
</variablelist>
|
||||
Sets the internal seed for the random number generator (the
|
||||
function <function>random</function>). Allowed values are
|
||||
floating-point numbers between 0 and 1, which are then
|
||||
multiplied by 2<superscript>31</>-1.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
The seed can also be set by invoking the
|
||||
<function>setseed</function> SQL function:
|
||||
|
||||
<programlisting>
|
||||
The seed can also be set by invoking the function
|
||||
<function>setseed</function>:
|
||||
<programlisting>
|
||||
SELECT setseed(<replaceable>value</replaceable>);
|
||||
</programlisting>
|
||||
</programlisting>
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term>TIME ZONE</term>
|
||||
<term>TIMEZONE</term>
|
||||
<term><literal>TIME ZONE</literal></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Sets the default time zone for your session. Arguments can be
|
||||
an SQL time interval constant, an integer or double precision
|
||||
constant, or a string representing a time zone name recognized
|
||||
by the host operating system.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Here are some typical values for time zone settings:
|
||||
<literal>>SET TIME ZONE <replaceable>value</></> is an alias
|
||||
for <literal>SET timezone TO <replaceable>value</></>. The
|
||||
syntax <literal>>SET TIME ZONE</literal> allows special syntax
|
||||
for the time zone specification. Here are examples of valid
|
||||
values:
|
||||
|
||||
<variablelist>
|
||||
<varlistentry>
|
||||
<term>'PST8PDT'</term>
|
||||
<term><literal>'PST8PDT'</literal></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Set the time zone for Berkeley, California.
|
||||
The time zone for Berkeley, California.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
<varlistentry>
|
||||
<term>'Portugal'</term>
|
||||
<term><literal>'Portugal'</literal></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Set the time zone for Portugal.
|
||||
The time zone for Portugal.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
<varlistentry>
|
||||
<term>'Europe/Rome'</term>
|
||||
<term><literal>'Europe/Rome'</literal></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Set the time zone for Italy.
|
||||
The time zone for Italy.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
<varlistentry>
|
||||
<term>7</term>
|
||||
<term><literal>7</literal></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Set the time zone to 7 hours offset west from GMT (equivalent
|
||||
The time zone to 7 hours offset west from UTC (equivalent
|
||||
to PDT).
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
<varlistentry>
|
||||
<term>INTERVAL '08:00' HOUR TO MINUTE</term>
|
||||
<term><literal>INTERVAL '08:00' HOUR TO MINUTE</literal></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Set the time zone to 8 hours offset west from GMT (equivalent
|
||||
The time zone to 8 hours offset west from UTC (equivalent
|
||||
to PST).
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
<varlistentry>
|
||||
<term>LOCAL</term>
|
||||
<term>DEFAULT</term>
|
||||
<term><literal>LOCAL</literal></term>
|
||||
<term><literal>DEFAULT</literal></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Set the time zone to your local time zone (the one that
|
||||
@@ -352,43 +216,19 @@ SELECT setseed(<replaceable>value</replaceable>);
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
</variablelist>
|
||||
</para>
|
||||
|
||||
<para>
|
||||
The available time zone names depend on your operating
|
||||
system. For example, on Linux
|
||||
<filename>/usr/share/zoneinfo</filename> contains the database
|
||||
of time zones; the names of the files in that directory can be
|
||||
used as parameters to this command.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
If an invalid time zone is specified, the time zone
|
||||
becomes GMT (on most systems anyway).
|
||||
</para>
|
||||
|
||||
<para>
|
||||
If the <envar>PGTZ</envar> environment variable is set in the frontend
|
||||
environment of a client based on <application>libpq</>, <application>libpq</> will automatically
|
||||
<command>SET TIMEZONE</command> to the value of
|
||||
<envar>PGTZ</envar> during connection start-up.
|
||||
See <xref linkend="datatype-datetime"> for more information
|
||||
about time zones.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
</variablelist>
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Use <xref linkend="SQL-SHOW" endterm="SQL-SHOW-title"> to show the
|
||||
current setting of a parameter.
|
||||
</para>
|
||||
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
<title>Diagnostics</title>
|
||||
<para>
|
||||
|
||||
|
||||
<variablelist>
|
||||
<varlistentry>
|
||||
<term><computeroutput>SET</computeroutput></term>
|
||||
@@ -400,8 +240,7 @@ SELECT setseed(<replaceable>value</replaceable>);
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><computeroutput>ERROR: '<replaceable>name</replaceable>' is not a
|
||||
valid option name</computeroutput></term>
|
||||
<term><computeroutput>ERROR: '<replaceable>name</replaceable>' is not a valid option name</computeroutput></term>
|
||||
<listitem>
|
||||
<para>
|
||||
The parameter you tried to set does not exist.
|
||||
@@ -410,8 +249,7 @@ SELECT setseed(<replaceable>value</replaceable>);
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><computeroutput>ERROR: '<replaceable>name</replaceable>':
|
||||
permission denied</computeroutput></term>
|
||||
<term><computeroutput>ERROR: '<replaceable>name</replaceable>': permission denied</computeroutput></term>
|
||||
<listitem>
|
||||
<para>
|
||||
You must be a superuser to alter certain settings.
|
||||
@@ -420,17 +258,14 @@ SELECT setseed(<replaceable>value</replaceable>);
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><computeroutput>ERROR: '<replaceable>name</replaceable>' cannot
|
||||
be changed after server start</computeroutput></term>
|
||||
<term><computeroutput>ERROR: '<replaceable>name</replaceable>' cannot be changed after server start</computeroutput></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Some parameters are fixed once the server is started.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
</variablelist>
|
||||
</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
@@ -438,81 +273,61 @@ SELECT setseed(<replaceable>value</replaceable>);
|
||||
|
||||
<para>
|
||||
The function <function>set_config</function> provides equivalent
|
||||
capability. See <xref linkend="functions-misc">.
|
||||
functionality. See <xref linkend="functions-misc">.
|
||||
</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
<title>Examples</title>
|
||||
|
||||
<para>
|
||||
Set the schema search path:
|
||||
<programlisting>
|
||||
SET search_path TO my_schema, public;
|
||||
</programlisting>
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Set the style of date to traditional
|
||||
<productname>PostgreSQL</productname> with European conventions:
|
||||
<screen>
|
||||
SET DATESTYLE TO PostgreSQL,European;
|
||||
</screen>
|
||||
<productname>POSTGRES</productname> with European conventions:
|
||||
<screen>
|
||||
SET datestyle TO postgres,european;
|
||||
</screen>
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Set the time zone for Berkeley, California, using quotes to
|
||||
preserve the uppercase spelling of the time zone name (note
|
||||
that the date style is <literal>PostgreSQL</literal> for this
|
||||
example):
|
||||
|
||||
<screen>
|
||||
preserve the uppercase spelling of the time zone name:
|
||||
<screen>
|
||||
SET TIME ZONE 'PST8PDT';
|
||||
SELECT CURRENT_TIMESTAMP AS today;
|
||||
today
|
||||
------------------------------------
|
||||
Tue Feb 26 07:32:21.42834 2002 PST
|
||||
</screen>
|
||||
</para>
|
||||
SELECT current_timestamp AS today;
|
||||
|
||||
<para>
|
||||
Set the time zone for Italy (note the required single quotes to handle
|
||||
the special characters):
|
||||
|
||||
<screen>
|
||||
SET TIME ZONE 'Europe/Rome';
|
||||
SELECT CURRENT_TIMESTAMP AS today;
|
||||
|
||||
today
|
||||
today
|
||||
-------------------------------
|
||||
2002-10-08 05:39:35.008271+02
|
||||
</screen>
|
||||
2003-04-29 15:02:01.218622-07
|
||||
</screen>
|
||||
</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1 id="R1-SQL-SET-3">
|
||||
<refsect1>
|
||||
<title>Compatibility</title>
|
||||
|
||||
<refsect2 id="R2-SQL-SET-4">
|
||||
<title>
|
||||
SQL92
|
||||
</title>
|
||||
|
||||
<para>
|
||||
<literal>SET TIME ZONE</literal>
|
||||
extends syntax defined in
|
||||
<acronym>SQL9x</acronym>. <acronym>SQL9x</acronym> allows
|
||||
only numeric time zone offsets while
|
||||
<productname>PostgreSQL</productname> allows full time zone
|
||||
specifier strings as well. All other <literal>SET</literal>
|
||||
features are
|
||||
<productname>PostgreSQL</productname> extensions.
|
||||
</para>
|
||||
</refsect2>
|
||||
<para>
|
||||
<literal>SET TIME ZONE</literal> extends syntax defined in the SQL
|
||||
standard. The standard allows only numeric time zone offsets while
|
||||
<productname>PostgreSQL</productname> allows more flexible
|
||||
time-zone specifications. All other <literal>SET</literal>
|
||||
features are <productname>PostgreSQL</productname> extensions.
|
||||
</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
<title>See Also</title>
|
||||
|
||||
<simpara>
|
||||
<xref linkend="SQL-SHOW" endterm="SQL-SHOW-title">,
|
||||
<xref linkend="SQL-RESET" endterm="SQL-RESET-title">,
|
||||
<xref linkend="sql-set-constraints" endterm="sql-set-constraints-title">,
|
||||
<xref linkend="sql-set-session-authorization" endterm="sql-set-session-authorization-title">,
|
||||
<xref linkend="sql-set-transaction" endterm="sql-set-transaction-title">
|
||||
</simpara>
|
||||
<simplelist type="inline">
|
||||
<member><xref linkend="SQL-RESET" endterm="SQL-RESET-title"></member>
|
||||
<member><xref linkend="SQL-SHOW" endterm="SQL-SHOW-title"></member>
|
||||
</simplelist>
|
||||
</refsect1>
|
||||
</refentry>
|
||||
|
||||
|
||||
Reference in New Issue
Block a user