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Primary key Vs Unique key

Posted on 2004-09-09
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Last Modified: 2008-01-09
Is there any point in declaring a primary key if I already have a unique clustered index on the primary key field(s)?
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Question by:billy21
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hkamal earned 350 total points
ID: 12018118
Yes, all tables should have a primary key
This just formalises your structure for inter-entity relationships
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by:jdlambert1
ID: 12018444
I agree with hkamal that all tables should have a primary key. I've heard many reasons why people didn't define them for some tables, but I don't buy the arguments. It's a best practice and a good habit. If you define a primary key on a table and it actually never "needed", no harm is done. If you don't define a primary key because you're "sure" it will never be needed, but you turn out to be wrong, great harm can be done. And I've seen a great many databases that were in extremely bad shape because of failures including lack of primary keys where people didn't think they were needed.
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