Re: Difference: Uniq. Constraint & Index ?

From: Robert Klemme <shortcutter_at_googlemail.com>
Date: Tue, 17 Oct 2006 17:31:29 +0200
Message-ID: <4pkbahFj579nU1@individual.net>

On 17.10.2006 03:20, DA Morgan wrote:
> However I would argue that you should never build a unique index.
>
> Here are just a few of the differences:
> 1. Unique constraints put an entry into user_indexes
> 2. Unique indexes do not create an entry in user_constraints
> 3. You can not defer an index
> 4. You can not disable an index (except FBI)
> 5. Unique indexes have no equivalent to NORELY
> 6. Unique indexes have no equivalent to NOVALIDATE

Hm... I could easily agree if it were not for the "never". Or maybe you meant "never build a unique index if you want to enforce a business constraint"?

Would you even use a unique constraint if the index does not reflect a business need but is just a performance enhancement measure?

Kind regards

robert Received on Tue Oct 17 2006 - 10:31:29 CDT