From http://www.postgresql.org/docs/8.1/interactive/triggers.html:
The trigger function must be defined before the trigger itself can be
created. The trigger function must be declared as a function taking no
arguments and returning type trigger. (The trigger function receives its
input through a specially-passed TriggerData structure, not in the form
of ordinary function arguments.)
On Thu, Dec 01, 2005 at 10:49:49PM +0000, Jozef Behran wrote:
>
> The following bug has been logged online:
>
> Bug reference: 2087
> Logged by: Jozef Behran
> Email address: jozef.behran@krs.sk
> PostgreSQL version: 8.1.0
> Operating system: Short answer: Mandrake 10.2. Long answer: Linux sarkan
> 2.6.11-6mdk #1 Tue Mar 22 16:04:32 CET 2005 i686 AMD Athlon(tm) Processor
> unknown GNU/Linux
> Description: Bogus error message on CREATE TRIGGER with a SQL
> function
> Details:
>
> Here is a sample shell session showing the SQL file and
> the output:
>
> $ cat bug.sql
> \set VERBOSITY verbose
>
> BEGIN;
>
> CREATE table pokus (
> id INT4,
> sval VARCHAR(100),
> sortsval VARCHAR(100),
> PRIMARY KEY(id)
> );
>
> CREATE FUNCTION tpokus(pokus) RETURNS pokus as $$
> SELECT $1.id,$1.sval,translate($1.sval,'abc','ABC');
> $$ LANGUAGE SQL IMMUTABLE;
>
> INSERT INTO pokus (id,sval) values (1,'aha');
>
> SELECT tpokus(pokus.*) FROM pokus;
>
> CREATE TRIGGER trigger_pokus
> BEFORE INSERT OR UPDATE
> ON pokus FOR EACH ROW
> EXECUTE PROCEDURE tpokus()
> ;
>
> ROLLBACK;
> $ psql -f bug.sql
> BEGIN
> psql:bug.sql:8: NOTICE: CREATE TABLE / PRIMARY KEY will create implicit
> index "pokus_pkey" for table "pokus"
> CREATE TABLE
> CREATE FUNCTION
> INSERT 0 1
> tpokus
> -------------
> (1,aha,AhA)
> (1 row)
>
> psql:bug.sql:22: ERROR: function tpokus() does not exist
> LOCATION: LookupFuncName, parse_func.c:1192
> ROLLBACK
> $ _
>
> The buggy error message is the line before `ROLLBACK' (the one saying that
> `tpokus' does not exist). The problem is that there *is* a function named
> `tpokus' (the previous SELECT executed the function without problems). If it
> is impossible to use a SQL function in a trigger, the error message should
> say so (for example ERROR: cannot use SQL function `name' in a trigger). If
> it is possible to have SQL-only triggers but the code is wrong, you should
> add a complete example of a SQL trigger into the documentation to show all
> the nasty quirks that may get into the way (for example the documentation
> says that the trigger must return `trigger' but it is impossible to declare
> such a SQL function).
>
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--
Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461