O kyrios Erik Thiele egrapse stis Mar 22, 2004 :
Did you check out the DEFERRABLE option on the constraint?
> hi,
>
> i have two tables
>
> create table a (x integer);
> create table b (y real);
>
> i have the special constraint that the sum of the number of rows in
> table a plus the number of rows in table b must be even.
>
> so there is a posibility of adding one element to a and one element to
> b, and again the constraint is met.
>
> but this of course does not work, since between adding the element to a
> and adding the element to b, the constraint is not met.
>
> so i cannot use a trigger.
>
> what i need is the execution of a check procedure at commit time. is
> that somehow possible?
>
> my database has much more tables than just a and b, and most time the other
> tables are modified and not a or b, so it would be nice to execute the
> constraint checking procedure only if a or b was modified.
>
> yes :) this question i asked in my former mail too, but I think it
> looked like there was a workaround and my problem was wrong. so i
> created this new kind of problem here to make things clearer.
>
>
> cu
> Erik
>
>
>
--
-Achilleus