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RE: FK Constraints

From: Jacques Kilchoer <>
Date: Mon, 19 Mar 2001 12:38:08 -0800
Message-ID: <>

> -----Original Message-----
> From: ramani akhil []
> We have a situation where are no relationships are
> defined at the database level. i.e no foreign keys
> constraints have established at the Database.  The
> application is still at the Development Stage.
> Everything is controlled at the application level.
> I as the DBA appose this design for Data security and
> also cannot reverse engineer from the tables into
> Designer. 
> Can you please share you pros / Cons.

If relationships are supposed to exist between tables in the database, then they should be enforced by integrity constraints.

I can think of a few reasons for not having the constraints: a) If there are bugs in the application that prevent the relationships from being enforced. Of course the best situation would be to fix the application and keep the constraints.

b) If the relationships exist logically but the application inserts rows in the tables in the "wrong order", i.e. in the child table first and then the parent table. Again the application should probably be re-written if time allows.

c) Performance reasons? I.e. without the extra constraints inserts in a table may happen slightly faster? I don't think I've ever heard of a real-life situation where the performance gain would be important enough to forego the data integrity ensured by constraints, but I suppose it could happen.

My short opinion: I see a lot more cons than pros.

any ignorant comments made are the sole responsibility of J. R. Kilchoer and should not reflect adversely upon my employer.

Jacques R. Kilchoer
(949) 754-8816
Quest Software, Inc.
8001 Irvine Center Drive
Irvine, California 92618
U.S.A. Received on Mon Mar 19 2001 - 14:38:08 CST

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