At 12:14 AM +0200 7/7/01, Fournier Jocelyn [Presence-PC] wrote:
>Hi,
>
>Is there any structural difference between a PRIMARY KEY and a UNIQUE key ?
>
>Thanks ;)
>
>Jocelyn Fournier
>Presence-PC
>www.presence-pc.com
They're mostly the same, with these differences:
There can only be one PRIMARY KEY per table, whereas you can have multiple
UNIQUE keys.
Any columns in a PRIMARY KEY must be declared NOT NULL; UNIQUE keys do
not have this restriction.
--
Paul DuBois, [EMAIL PROTECTED]
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