Re: Trigger question

I got it.
But here's what I need to do: after any modification on the table, I
must run a procedure that will do some calculation, and then set these
values for each row. This calculation establishes relationships between
rows, and builds logically a tree. To accomplish all that, first I need
to unset some values, so I decided to use the BEFORE trigger to unset
these values, and the AFTER trigger to do this calculation.

Will I have to use explicit queries? And what's the real purpose of the
AFTER trigger?

Thanks

Tom Lane wrote:
>
> Nelio Alves Pereira Filho <nelio(at)ifx(dot)com(dot)br> writes:
> > create trigger set_counter after insert or update on nivel
> > for each row execute procedure set_counter();
>
> > The problem is that after I insert something, count value is still -1,
> > not 0!
>
> You want a BEFORE trigger, not an AFTER trigger. AFTER is too late
> to affect the contents of the stored row.
>
> regards, tom lane

--
Nelio Alves Pereira Filho
IFX Networks
Sao Paulo / Brazil