On Mon, Mar 22, 2004 at 10:20:31 +0100, Erik Thiele <[EMAIL PROTECTED]> wrote: > 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.
Does the above mean that the number of rows in a is equal to the number of rows in b or that their sum is divisible by 2? > 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? Do the real tables have candidate keys? If so you can use foreign key references to pair a row in a to a row b (though I am not sure this is what your real constraint is). ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
