Re: Unique index vs. unique constraint

From: Richard Gaston <itdiners_at_mnl.sequel.net>
Date: Fri, 27 Aug 1999 09:07:47 +0800
Message-ID: <7q4nsn$7e6$1@bohol.infocom.sequel.net>

I think unique constraints are implemented as unique indexes in oracle. Oracle will create a unique index for the column(s) you declare unique in a constraint. So apparently, there's no real difference between the two.

As to why you'd prefer one over the other, I don't know. Taste?

Michael Hjorth <michael_hjorth_at_my-deja.com> wrote in message news:7q2vo5$c0g$1_at_nnrp1.deja.com...
> What is the functional difference between a unique index and a unique
> constraint?
> I know the latter has a constraint as well as the index, but apparently
> it enforces the same restrictions on the database as the unique index.
> Or did I get it wrong?
> Why would I prefer one over the other in a particular case?
>
> Thank you for any comments.
>
> Michael.
>
>
> Sent via Deja.com http://www.deja.com/
> Share what you know. Learn what you don't.
Received on Thu Aug 26 1999 - 20:07:47 CDT