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From: Erik Thiele <[email protected]>
To: [email protected]
Subject: special integrity constraints
Date: Mon, 22 Mar 2004 10:20:31 +0100
Message-ID: <[email protected]> (raw)

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


-- 
Erik Thiele

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