[ FOR [ EACH ] { ROW | STATEMENT } ]

[ WHEN ( <replaceable class="parameter">condition</replaceable> ) ]

EXECUTE PROCEDURE <replaceable class="PARAMETER">function_name</replaceable> ( <replaceable class="PARAMETER">arguments</replaceable> )

<phrase>where <replaceable class="parameter">event</replaceable> can be one of:</phrase>

INSERT

UPDATE [ OF <replaceable class="parameter">column_name</replaceable> [, ... ] ]

DELETE

TRUNCATE

</synopsis>

</refsynopsisdiv>

<term><replaceable class="parameter">event</replaceable></term>

<listitem>

<para>

One of <command>INSERT</command>, <command>UPDATE</command>,

<command>DELETE</command>, or <command>TRUNCATE</command>;

One of <literal>INSERT</literal>, <literal>UPDATE</literal>,

<literal>DELETE</literal>, or <literal>TRUNCATE</literal>;

this specifies the event that will fire the trigger. Multiple

events can be specified using <literal>OR</literal>.

</para>

<para>

For <command>UPDATE</command> triggers, it is possible to

For <literal>UPDATE</literal> events, it is possible to

specify a list of columns using this syntax:

<synopsis>

UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</replaceable> ... ]

</synopsis>

The trigger will only fire if at least one of the listed columns

is mentioned as a target of theupdate.

is mentioned as a target of the<command>UPDATE</> command.

</para>

<para>

<literal>UPDATEINSTEAD OF</>triggers do not support lists of columns.

<literal>INSTEAD OF UPDATE</>events do not support lists of columns.

</para>

</listitem>

</varlistentry>

</para>

<para>

A column-specific trigger (<literal>FORUPDATE OF

<replaceable>column_name</replaceable></literal>) will fire when any

A column-specific trigger (one defined using the<literal>UPDATE OF

<replaceable>column_name</replaceable></literal> syntax) will fire when any

of its columns are listed as targets in the <command>UPDATE</>

command's <literal>SET</> list. It is possible for a column's value

to change even when the trigger is not fired, because changes made to the