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Diffstat (limited to 'doc/src/sgml/trigger.sgml')
| -rw-r--r-- | doc/src/sgml/trigger.sgml | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml index 942aeb4b7e..a13925b066 100644 --- a/doc/src/sgml/trigger.sgml +++ b/doc/src/sgml/trigger.sgml @@ -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> |