Hello Peter I checked code, and I don't think so this is good.
A design of optional NULL is going to inconsistent syntax. RETURN (OLD, NEW, NULL, /* nothing */) is not consistent But my main argument is not intuitive behave of BEFORE triggers after this change. When somebody write BEFORE trigger function like: BEGIN RAISE NOTICE '%', NEW.x; RETURN; END; then don't expect so all rows will be lost. Preferred default return value for BEFORE INSERT UPDATE trigger should be NEW, and for DELETE trigger should be OLD - not NULL. And because we cannot to distinct between BEFORE and AFTER trigger in parser, I propose don't change current behave. Current behave is not too friendly - but is consistent with simple rules. Regards Pavel 2012/1/2 Peter Eisentraut <pete...@gmx.net>: > On mån, 2011-02-28 at 19:07 +0200, Peter Eisentraut wrote: >> PL/pgSQL trigger functions currently require a value to be returned, >> even though that value is not used for anything in case of a trigger >> fired AFTER. I was wondering if we could relax that. It would make >> things a bit more robust and produce clearer PL/pgSQL code. The >> specific case I'm concerned about is that a trigger function could >> accidentally be run in a BEFORE trigger even though it was not meant for >> that. It is common practice that trigger functions for AFTER triggers >> return NULL, which would have unpleasant effects if used in a BEFORE >> trigger. >> >> I think it is very uncommon to have the same function usable for BEFORE >> and AFTER triggers, so it would be valuable to have coding support >> specifically for AFTER triggers. We could just allow RETURN without >> argument, or perhaps no RETURN at all. > > Here is a patch for that. > > One thing that I'm concerned about with this is that it treats a plain > RETURN in a BEFORE trigger as RETURN NULL, whereas arguably it should be > an error. I haven't found a good way to handle that yet, but I'll keep > looking. > > > > -- > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers > -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
