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Difference beteen keys

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Topic

nishu81
Starting Member

11 Posts

Posted - 2009-12-17 : 09:37:12

Is candidate key is same as unique key??

I have read some where unique key can be null (but only once)
is candidate key can also be null once??

tkizer
Almighty SQL Goddess

38200 Posts

Posted - 2009-12-17 : 10:28:55

Yes. The name means that it is a candidate for the primary key constraint. You can only have one PK, so other candidates are set as unique keys.

Tara Kizer
Microsoft MVP for Windows Server System - SQL Server
http://weblogs.sqlteam.com/tarad/

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