Re: UNIQUE &NOT NULL vs PK

From: Connor McDonald <connor_mcdonald_at_yahoo.com>
Date: Mon, 08 Nov 1999 19:04:54 +0800
Message-ID: <3826AE56.3513@yahoo.com>

Nandakumar wrote:
>
> could someone list out the advantages/disadvantages of defining a column
> with PRIMARY KEY constraint over UNIQUE and NOT NULL constraint?
>
> i am wondering where the diff. between these two exists?
>
> ... in storage of the constraint ???
> ... ability to be REFERENCEd in foreign tables ???
> ... INDEXabilty ???
> ... or something else ???
>
> thanks in advance for your valuable responses.
> regards
> Nanda
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.

To update a join - you need a primary key, a unique index (or even a unique constraint I think) won't cut it...

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Connor McDonald
"These views mine, no-one elses etc etc" connor_mcdonald_at_yahoo.com

"Some days you're the pigeon, and some days you're the statue." Received on Mon Nov 08 1999 - 05:04:54 CST