Clarify trigger function return convention, per Thomas Hallgren.

This commit is contained in:
Tom Lane 2004-08-13 16:17:19 +00:00
parent 79f9ee9d15
commit 5a67d7618f

View File

@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/trigger.sgml,v 1.35 2004/03/03 22:22:24 neilc Exp $
$PostgreSQL: pgsql/doc/src/sgml/trigger.sgml,v 1.36 2004/08/13 16:17:19 tgl Exp $
-->
<chapter id="triggers">
@ -431,8 +431,10 @@ typedef struct Trigger
</para>
<para>
A trigger function must return either <symbol>NULL</> or a
<structname>HeapTuple</> pointer. Be careful to return either
A trigger function must return either a
<structname>HeapTuple</> pointer or a <symbol>NULL</> pointer
(<emphasis>not</> a SQL NULL, that is, do not set isNull true).
Be careful to return either
<structfield>tg_trigtuple</> or <structfield>tg_newtuple</>,
as appropriate, if you don't want to modify the row being operated on.
</para>