Re: Why no database constraints?
From: <joe_celko_at_my-deja.com>
Date: 2000/03/27
Message-ID: <8bnqrq$q5$1_at_nnrp1.deja.com>#1/1
Date: 2000/03/27
Message-ID: <8bnqrq$q5$1_at_nnrp1.deja.com>#1/1
>> It seems to me that so much business logic could be implemented
through database constraints spanning multiple tables instead of in
stored procedures/triggers. Why does none of the major RDBMS servers
allow such constraints? <<
Yes, this is called CREATE ASSERTION in SQL-92. An assertion is a CHECK () constraint that belongs to the database as a whole. The trouble with table constraints is that it will always be true on an empty table.
Ron Ross and other have proposed the idea of a declarative business rules language in a separate server from the database which would control temporal rules as well as constraints.
--CELKO--
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Received on Mon Mar 27 2000 - 00:00:00 CEST