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#1 (**permalink**) 02-26-2008, 04:17 PM

My understanding is that unlike CHAEK and FOREIGN KEY constraints, we
cannot have UNIQUE ones NOT ENFORCED, and the reason is very simple:
UNIQUE constraints are implemented as UNIQUE indexes. One cannot turn
off uniquenedss of an index easily

Am I correct?

#2 (**permalink**) 02-26-2008, 04:18 PM

AK wrote:
> My understanding is that unlike CHAEK and FOREIGN KEY constraints, we
> cannot have UNIQUE ones NOT ENFORCED, and the reason is very simple:
> UNIQUE constraints are implemented as UNIQUE indexes. One cannot turn
> off uniquenedss of an index easily
>
> Am I correct?
That is correct. DB2 could allow informational uniqueness. Nothing
speaks against it.
That would imply some tweaking of the catalogs though or we'd end up
with informational idedxes which is a tad weird for my taste at least.

Cheers
Serge

--
Serge Rielau
DB2 SQL Compiler Development
IBM Toronto Lab

#3 (**permalink**) 02-26-2008, 04:18 PM

Serge,

thank you for answering!

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Turn On/Off Foreign Key Constraints?