Re: Difference: Uniq. Constraint & Index ?

> The basis for my question was that I've frequently read the rule of
> thumb "if it is a business constraint, use a DB constraint for
> enforcement - otherwise use an index". This seems a bit conflicting
> with your general preference of constraints. Or do you think this rule
> of thumb to be wrong?

Even assuming that the above is correct, if it is not a business rule, then why are we using a unique index? The fact that the column(s) should be unique *is* a business rule. Can you provide an example of a column(s) being unique that is not defined by a business rule? I can't.

HTH,
Brian

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Brian Peasland
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