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PRIMARY KEY VS UNIQUE KEY*


PRIMARY KEY VS UNIQUE KEY*

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Grant Fritchey
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A pretty common use of unique keys is when you have an artificial primary key for a table, the single most common example is the identity field, but you still need to define the logical key (and any other alternate keys) in order to prevent duplicate storage within the table.

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Grant Fritchey (7/30/2013)
A pretty common use of unique keys is when you have an artificial primary key for a table, the single most common example is the identity field, but you still need to define the logical key (and any other alternate keys) in order to prevent duplicate storage within the table.


True dat. A common scenario is in data warehousing, where you have a clustered index on the surrogate key of a dimension, and a unique index on the business key of the dimension.



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Koen Verbeeck (7/30/2013)
Grant Fritchey (7/30/2013)
A pretty common use of unique keys is when you have an artificial primary key for a table, the single most common example is the identity field, but you still need to define the logical key (and any other alternate keys) in order to prevent duplicate storage within the table.


True dat. A common scenario is in data warehousing, where you have a clustered index on the surrogate key of a dimension, and a unique index on the business key of the dimension.


+1 excellent example.

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