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Topic: What’s the difference between a primary key and a unique key
Sachin Jain
30 Oct 2010 at 02:29 AM
What’s the difference between a primary key and a unique key?

Re: What’s the difference between a primary key and a unique key
Gaurav
31 Oct 2010 at 10:58 PM
Both primary key and unique enforce uniqueness of the column on which they are defined. But by default primary key creates a clustered index on the column, where are unique creates a nonclustered index by default. Another major difference is that, primary key doesn’t allow NULLs, but unique key allows one NULL only.
Total Replies: 1
 
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