Re: update in rule

On Wed, 7 Nov 2001, Radoslaw Stachowiak wrote:

> *** Stephan Szabo <sszabo@megazone23.bigpanda.com> [Wednesday, 17.October.2001, 12:04 -0700]:
> > create function adresses_trigger() returns opaque as '
> > begin
> >  NEW.date_maj := now();
> >  return NEW;
> > end;' language 'plpgsql';
> > create trigger tr before update on adresses for each row execute
> >  procedure adresses_trigger();
>
> why sould I use before (instead of after)?
> isnt it a little dangerous in transactions? /hope not/
>
> I know difference between both forms. The question is rather about if
> timestamp updating shouldnt be run AFTER update which I think is closer
> to a real world situations (of course evth vary). But maybe there are
> some probles with after, which I dont know about?

It's pretty much 6 of one, half dozen of another AFAICS.  This doesn't
actually update the table per-se, it updates the copy of the row that
you've asked to update the row to.  The actual update changes the date
column.