On Jan 13, 2006, at 21:42 , Leandro Guimarães Faria Corcete DUTRA wrote:
> If you still declare the natural key(s) as UNIQUEs, you have just made
> performance worse. Now there are two keys to be checked on UPDATEs
> and
> INSERTs, two indexes to be updated, and probably a SEQUENCE too.
For UPDATEs and INSERTs, the "proper" primary key also needs to be
checked, but keys are used for more than just checking uniqueness:
they're also often used in JOINs. Joining against a single integer
I'd think it quite a different proposition (I'd think faster in terms
of performance) than joining against, say, a text column or a
composite key.
Michael Glaesemann
grzm myrealbox com