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Should I index a view that is converting data types?

  • December 10, 2010 at 4:52 pm

    #1261243

    traughberk (12/10/2010)

    That's what I was struggling with. How unique does something need to be in order to be considered "selective"? I have SSN, dates, and some other data, but none of it makes a record truly unique.

    A given column should be about 95% unique to be considered for an index, by itself. In combination, with other columns, again, the combination should break 95%. That, of course, is a rough rule of thumb.

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