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DB2 - What is the difference between primary key & unique index ?




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asked mar August 3, 2014 05:35 AM  

What is the difference between primary key & unique index ?


           

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answered By Mswami   0  
Primary Key: A relational database constraint.  Primary key consists of one or more columns that uniquely identify a row in the table.  For a normalized relation, there is one designated primary key.

Unique index: a physical object that stores only unique values. There can be one or more unique indexes on a table.
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