Re: Test if Data for a Field is UNIQUE

Walt wrote:

> I don't think there's any functional difference between
>
> CREATE UNIQUE INDEX ...
>
> and
>
> ALTER TABLE FOO
> ADD CONSTRAINT BAR
> UNIQUE (COL1)
Actually there is. One, of course, being the ability to defer or disable a constraint ... but almost as important is the fact that with a UNIQUE INDEX no entry can be found in user_constraints whereas with the creation of a UNIQUE CONSTRAINT you will find entries in both user_constraints and user_indexes.

I advise my students to NEVER build a unique index.

-- 
Daniel A. Morgan
http://www.psoug.org
damorgan_at_x.washington.edu
(replace x with u to respond)