postgresql/doc/src/sgml/ref/truncate.sgml

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$Header: /cvsroot/pgsql/doc/src/sgml/ref/truncate.sgml,v 1.5 2001/12/08 03:24:39 thomas Exp $
PostgreSQL documentation
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<refentry id="SQL-TRUNCATE">
<refmeta>
<refentrytitle id="SQL-TRUNCATE-TITLE">
TRUNCATE
</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
<refnamediv>
<refname>
TRUNCATE
</refname>
<refpurpose>
empty a table
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<refsynopsisdivinfo>
<date>1999-07-20</date>
</refsynopsisdivinfo>
<synopsis>
TRUNCATE [ TABLE ] <replaceable class="PARAMETER">name</replaceable>
</synopsis>
<refsect2 id="R2-SQL-TRUNCATE-1">
<refsect2info>
<date>1998-09-08</date>
</refsect2info>
<title>
Inputs
</title>
<para>
<variablelist>
<varlistentry>
<term><replaceable class="PARAMETER">name</replaceable></term>
<listitem>
<para>
The name of the table to be truncated.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect2>
<refsect2 id="R2-SQL-TRUNCATE-2">
<refsect2info>
<date>1998-09-08</date>
</refsect2info>
<title>
Outputs
</title>
<para>
<variablelist>
<varlistentry>
<term><computeroutput>
TRUNCATE
</computeroutput></term>
<listitem>
<para>
Message returned if the table is successfully truncated.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect2>
</refsynopsisdiv>
<refsect1 id="R1-SQL-TRUNCATE-1">
<refsect1info>
<date>1998-09-08</date>
</refsect1info>
<title>
Description
</title>
<para>
<command>TRUNCATE</command> quickly removes all rows from a
table. It has the same effect as an unqualified
<command>DELETE</command> but since it does not actually scan the
table it is faster. This is most useful on large tables.
</para>
<para>
<command>TRUNCATE</command> cannot be executed inside a transaction
block (<command>BEGIN</>/<command>COMMIT</> pair), because there is
no way to roll it back.
</para>
</refsect1>
<refsect1 id="R1-SQL-TRUNCATE-2">
<title>
Usage
</title>
<para>
Truncate the table <literal>bigtable</literal>:
<programlisting>
TRUNCATE TABLE bigtable;
</programlisting>
</para>
</refsect1>
<refsect1 id="R1-SQL-TRUNCATE-3">
<title>
Compatibility
</title>
<refsect2 id="R2-SQL-TRUNCATE-4">
<refsect2info>
<date>1998-09-08</date>
</refsect2info>
<title>
SQL92
</title>
<para>
There is no <command>TRUNCATE</command> in <acronym>SQL92</acronym>.
</para>
</refsect2>
</refsect1>
</refentry>
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