Re: db constraints evaluation question
From: <joe_celko_at_my-deja.com>
Date: 2000/03/17
Message-ID: <8atkt8$lfg$1_at_nnrp1.deja.com>#1/1
Date: 2000/03/17
Message-ID: <8atkt8$lfg$1_at_nnrp1.deja.com>#1/1
>> If I have a set of constraints in my (e.g. object-oriented) db and a
transaction which performs several update, delete etc. operations, how
do I determine which deferred constraint checks are needed at the end
of the transaction - to find out if my data still is in onsistent/valid
state or not. <<
The SQL-92 Standard says that ALL constraints -- defered or not -- must be met when the transaction is finished. Otherwise, you get a ROLLBACK WORK and a set of error messages which tell you which constraints were violated. Deferred constraints are turned off only until you turn them back on, or try to COMMIT WORK.
--CELKO--
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Received on Fri Mar 17 2000 - 00:00:00 CET