Jeff Boyce wrote:
thanks for this i appreciate your reply. From your suggestion, I take it
that validation would be better through the form than through the tables.

It would be simpler to use form-level validation, since there are
user-interface tools that assist. That doesn't necessarily make it
"better".

Phil, I'd urge you to read this series of three short articles on this
very issue (I'm pretty sure I've previously referred Jeff here g):

Mop the Floor and Fix the Leak
by Joe Celko

http://www.dbazine.com/ofinterest/oi-articles/celko25/

"The poster was asked about some basic data integrity issue and in the
discussion he replied that all the validation would be done in the
front end application program, so we did not have to bother with
constraints on the [database] side. Golly gee whiz, do you suppose that
might be a bad idea? Let's just list some of the assumptions and
situations required for this approach to work..."

Jamie.

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