Date: Mon, 22 Mar 2004 12:13:29 +0200 (EET)
From: Achilleus Mantzios <achill@matrix.gatewaynet.com>
To: Erik Thiele <erik@thiele-hydraulik.de>
Cc: pgsql-sql@postgresql.org
Subject: Re: special integrity constraints
In-Reply-To: <20040322102031.6a6f0b77.erik@thiele-hydraulik.de>
Message-ID: <Pine.LNX.4.44.0403221212500.31407-100000@matrix.gatewaynet.com>
MIME-Version: 1.0
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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