Re: functions and triggers

On Tue, 20 Aug 2002, Martin Marques wrote:

> Quoting Stephan Szabo <sszabo(at)megazone23(dot)bigpanda(dot)com>:
>
> >
> > > The problemas are two:
> > >
> > > 1) when I try to create the trigger, it says that the function doesn't
> > exist.
> > > Why is this happening?
> >
> > You should probably show us what you were trying to do, but I'm going to
> > guess that the function doesn't have the right signature. On
> > current versions, Trigger functions should return opaque and take no
> > arguments (any arguments given on the create trigger line are passed
> > in a different fashion).
>
> I have this function which works OK.
>
> CREATE FUNCTION ahora (integer) RETURNS integer AS '
> UPDATE usuarios SET tmodif = now()
> WHERE codigo = $1;
> SELECT 1 as RESULT;
> ' LANGUAGE SQL

Trigger functions have no args and return opaque and I don't think you
can use sql language functions, but I'm not sure. Something like:

create function ahora_trigger() returns opaque as '
begin
NEW.tmodif := now();
return NEW;
end;'
language 'plpgsql';

should work as a before update trigger.