Message-ID: <3DAC626B.4DEB45E8@Yahoo.com>
Date: Tue, 15 Oct 2002 14:46:03 -0400
From: Jan Wieck <JanWieck@Yahoo.com>
Organization: Home
MIME-Version: 1.0
To: Brian Blaha <bblaha@umr.edu>
Cc: pgsql-sql@postgresql.org
Subject: Re: SQL function triggers
References: <3DABB04B.8000104@umr.edu>
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Brian Blaha wrote:
> 
> I would like to write a function as a set of SQL statements, and then
> use that function
> in a trigger. However, since triggers require a return type of opaque,
> and SQL functions
> cannot return type opaque, this doesn't look possible. Am I missing
> something? The SQL
> that I would expect to do this is below. Incidentally, on an insert,
> would the trigger fire
> once, twice, or infinitely?
> 
> create table test(
> a integer,
> b integer
> ) without oids;
> 
> create function test_func( test.a%TYPE )
> RETURNS ?????
> AS
> 'update test set b = a where a = $1;'
> language SQL
> with (isstrict);
> 
> create trigger test_trig after update
> on test for each row
> execute procedure test_func( a );

If you intend to modify the updated row only with information available
in the row itself (as in your example), a BEFORE trigger in PL/pgSQL
modifying and returning NEW should get the job done.


Jan

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