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Re: Unique contraints vs. Unique indexes

From: Connor McDonald <connor_mcdonald_at_yahoo.com>
Date: Mon, 13 Aug 2001 19:39:18 +0100
Message-ID: <3B781ED6.EB4@yahoo.com>

James Williams wrote:
>
> I am about to build a data warehouse that will eventually be 1 TB.
>
> A PK's are going to have non_unique indexes and so that they can be
> deferrable.
>
> What are the heavy hitters opinions on this?

A non-unique index is less "attractive" to the optimiser than a unique one, but deferrable primary keys are very nice when removing duplicates (ie cleaning up your data)...

... I'd look at using deferrable constraints where you think they will be appropriate rather then as a rule.

hth
connor

-- 
==============================
Connor McDonald

http://www.oracledba.co.uk

"Some days you're the pigeon, some days you're the statue..."
Received on Mon Aug 13 2001 - 13:39:18 CDT

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