drop_trigger.sgml

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

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$PostgreSQL: pgsql/doc/src/sgml/ref/drop_trigger.sgml,v 1.19 2004/09/20 00:04:19 neilc Exp $
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<refentry id="SQL-DROPTRIGGER">
 <refmeta>
  <refentrytitle id="SQL-DROPTRIGGER-TITLE">DROP TRIGGER</refentrytitle>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>DROP TRIGGER</refname>
  <refpurpose>remove a trigger</refpurpose> 
 </refnamediv>            

 <indexterm zone="sql-droptrigger">
  <primary>DROP TRIGGER</primary>
 </indexterm>

 <refsynopsisdiv>
<synopsis>
DROP TRIGGER <replaceable class="PARAMETER">name</replaceable> ON <replaceable class="PARAMETER">table</replaceable> [ CASCADE | RESTRICT ]
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>DROP TRIGGER</command> will remove an existing
   trigger definition. To execute this command, the current
   user must be the owner of the table for which the trigger is defined.
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

  <variablelist>
   <varlistentry>
    <term><replaceable class="PARAMETER">name</replaceable></term>
    <listitem>
     <para>
      The name of the trigger to remove.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="PARAMETER">table</replaceable></term>
    <listitem>
     <para>
      The name (optionally schema-qualified) of the table for which
      the trigger is defined.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>CASCADE</literal></term>
    <listitem>
     <para>
      Automatically drop objects that depend on the trigger.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>RESTRICT</literal></term>
    <listitem>
     <para>
      Refuse to drop the trigger if any objects depend on it.  This is
      the default.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>

 <refsect1 id="SQL-DROPTRIGGER-examples">
  <title>Examples</title>

  <para>
   Destroy the trigger <literal>if_dist_exists</literal> on the table
   <literal>films</literal>:

<programlisting>
DROP TRIGGER if_dist_exists ON films;
</programlisting>
  </para>
 </refsect1>
 
 <refsect1 id="SQL-DROPTRIGGER-compatibility">
  <title>Compatibility</title>
  
  <para>
   The <command>DROP TRIGGER</command> statement in
   <productname>PostgreSQL</productname> is incompatible with the SQL
   standard.  In the SQL standard, trigger names are not local to
   tables, so the command is simply <literal>DROP TRIGGER
   <replaceable>name</replaceable></literal>.
  </para>
 </refsect1>

 <refsect1>
  <title>See Also</title>

  <simplelist type="inline">
   <member><xref linkend="sql-createtrigger" endterm="sql-createtrigger-title"></member>
  </simplelist>
 </refsect1>

</refentry>

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