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Null values and unique constraints
Message
From
02/05/2001 16:51:33
Michael Levy
Cincinnati, Ohio, United States
 
 
To
02/05/2001 15:06:36
Jorge Haro
Independent Consultant
Juarez, Mexico
General information
Forum:
Microsoft SQL Server
Category:
Database management
Title:
Re: Null values and unique constraints
Miscellaneous
Thread ID:
00502695
Message ID:
00502762
Views:
15
The UNIQUE constrait differs from the PRIMARY KEY constraint in that you can have NULLs - but only one!

You can always implement a trigger that tests for uniqueness and ignores NULLs

-Mike
Michael Levy
MCSD, MCDBA
ma_levy@hotmail.com
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