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From:Paul DuBois Date:July 6 2001 10:49pm
Subject:Re: Perhaps a stupid question about KEY...
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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, paul@stripped
Thread
Perhaps a stupid question about KEY...Fournier Jocelyn [Presence-PC]7 Jul
  • Re: Perhaps a stupid question about KEY...Paul DuBois7 Jul
  • Re: Perhaps a stupid question about KEY...Ken Sommers7 Jul
    • Re: Perhaps a stupid question about KEY...Jeremy Zawodny7 Jul
  • Re: Perhaps a stupid question about KEY...Tonu Samuel8 Jul