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Message Posted: Fri, 05 Jan 2007 @ 11:26:18 GMT


     
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Subj:   Re: Creating tables 50% to 90% of columns as unique primary index
 
From:   Ferry, Craig

In my opinion, you should not be using your primary index to enforce uniqueness. Your primary index should be used as something that you will use as joins to other tables. It still may be a unique primary index, but may not be one also. The primary index also controls how the data is skewed across your amps. To me, you need to balance the skew and the ability to join when creating this index, not using it for just one or the other.

If you are looking at a way of keeping duplicate rows out of the table, creating a SET (as opposed to MULTISET) table is a method I've used. There are some drawbacks to that as well as all updates and inserts will be slower as each record inserted or changed must be validated against existing records first to ensure the uniqueness isn't impacted.


Craig



     
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