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Support statement-level ON TRUNCATE triggers. Simon Riggs

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This commit is contained in:
Tom Lane
2008-03-28 00:21:56 +00:00
parent 107b3d0c23
commit 7692d8d5b7
23 changed files with 454 additions and 83 deletions
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27
doc/src/sgml/trigger.sgml
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@@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/trigger.sgml,v 1.51 2007/12/03 23:49:51 tgl Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/trigger.sgml,v 1.52 2008/03/28 00:21:55 tgl Exp $ -->
<chapter id="triggers">
<title>Triggers</title>
@@ -36,14 +36,15 @@
performed. Triggers can be defined to execute either before or after any
<command>INSERT</command>, <command>UPDATE</command>, or
<command>DELETE</command> operation, either once per modified row,
or once per <acronym>SQL</acronym> statement.
If a trigger event occurs, the trigger's function is called
at the appropriate time to handle the event.
or once per <acronym>SQL</acronym> statement. Triggers can also fire
for <command>TRUNCATE</command> statements. If a trigger event occurs,
the trigger's function is called at the appropriate time to handle the
event.
</para>
<para>
The trigger function must be defined before the trigger itself can be
created. The trigger function must be declared as a
created. The trigger function must be declared as a
function taking no arguments and returning type <literal>trigger</>.
(The trigger function receives its input through a specially-passed
<structname>TriggerData</> structure, not in the form of ordinary function
@@ -69,7 +70,8 @@
in the execution of any applicable per-statement triggers. These
two types of triggers are sometimes called <firstterm>row-level</>
triggers and <firstterm>statement-level</> triggers,
respectively.
respectively. Triggers on <command>TRUNCATE</command> may only be
defined at statement-level.
</para>
<para>
@@ -398,6 +400,15 @@ typedef struct TriggerData
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>TRIGGER_FIRED_BY_TRUNCATE(tg_event)</literal></term>
<listitem>
<para>
Returns true if the trigger was fired by a <command>TRUNCATE</command> command.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</listitem>
@@ -630,10 +641,10 @@ CREATE FUNCTION trigf() RETURNS trigger
AS '<replaceable>filename</>'
LANGUAGE C;
CREATE TRIGGER tbefore BEFORE INSERT OR UPDATE OR DELETE ON ttest
CREATE TRIGGER tbefore BEFORE INSERT OR UPDATE OR DELETE ON ttest
FOR EACH ROW EXECUTE PROCEDURE trigf();
CREATE TRIGGER tafter AFTER INSERT OR UPDATE OR DELETE ON ttest
CREATE TRIGGER tafter AFTER INSERT OR UPDATE OR DELETE ON ttest
FOR EACH ROW EXECUTE PROCEDURE trigf();
</programlisting>
</para>