From: Erik Thiele <erik@thiele-hydraulik.de>
To: pgsql-sql@postgresql.org
Subject: special integrity constraints
Date: Mon, 22 Mar 2004 10:20:31 +0100
Message-ID: <20040322102031.6a6f0b77.erik@thiele-hydraulik.de> (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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To: pgsql-sql@postgresql.org
Cc: erik@thiele-hydraulik.de
Subject: Re: special integrity constraints
In-Reply-To: <20040322102031.6a6f0b77.erik@thiele-hydraulik.de>
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