Message-ID: <3FCF7ECA.5060200@klaster.net>
Date: Thu, 04 Dec 2003 19:36:58 +0100
From: Tomasz Myrta <jasiek@klaster.net>
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To: Jeff Kowalczyk <jtk@yahoo.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: Trigger plpgsql function, how to test if OLD is set?
References: <pan.2003.12.04.18.17.53.593118@yahoo.com>
In-Reply-To: <pan.2003.12.04.18.17.53.593118@yahoo.com>
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Dnia 2003-12-04 19:18, Użytkownik Jeff Kowalczyk napisał:
> When this trigger runs on INSERT operations, the OLD variable is not
> yet set, and the trigger function returns an error.
> 
> Can anyone suggest a more sensible way to check for OLD before including
> it in my expression, or another shortcut? Thanks.
> 
> CREATE OR REPLACE FUNCTION orders_initordercharges () RETURNS "trigger"
>     AS '
> BEGIN
>   -- Check that no ordercharges exist for this orderid
>   IF (SELECT COUNT(orderchargeid) FROM ordercharges WHERE orderid=NEW.orderid OR orderid=OLD.orderid)=0 THEN
>     -- Insert standard initial set of ordercharges
>     INSERT INTO ordercharges (orderid, orderchargecode) VALUES (NEW.orderid,\'SALE\'); 
>     INSERT INTO ordercharges (orderid, orderchargecode) VALUES (NEW.orderid,\'S&H\'); 
>   END IF;
>   RETURN NEW;
> END;
> '
>     LANGUAGE plpgsql;

You can always check whether your trigger has been fired as insert or 
update trigger.

DECLARE
   old_orderid  integer;
BEGIN
   if TG_OP=''UPDATE'' then
      old_orderid=OLD.orderid;
   else
      old_orderid=-1;
   end if;
...

Regards,
Tomasz Myrta