michael.kaufmann (7/22/2010)

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Wayne,

first of all thank you for compiling a QotD.
However, I do not quite agree with the solution.

'Unique' is just taking the definition of a clusterd or non-clustered index a step further.
'with included columns' and 'filtered' again are non-clustered indexes (with advanced features).
So I don't see them as individual types, but sub-types at best.

Hence it comes down to 5 types (why I got it wrong):
- clustered
- non-clustered
- full-text
- spatial
- XML

I assume, though, that this is another wording issue ; nevertheless an excellent lesson having to recap what index types there are.

Thanks,
Michael

hrvoje.piasevoli (7/22/2010)

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Would missing and unused make it 10?:)

WayneS (7/22/2010)

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I would agree that Unique, filtered and included indexes are a sub-type of the clustered (for Unique) or non-clustered index types. However, according to the latest Microsoft documentation, they are a type of index. I'm not going to base a QotD off of what I believe it should be without any documentation to back me up.

You might want to take a look at SQL 2008 (R1) BOL for index types at http://msdn.microsoft.com/en-us/library/ms175049.aspx%28sql.100%29 - here they list 9 (they included Indexed Views). Since an Indexed View is a type of a view, physically manifested by having a clustered index and optionally having non-clustered indexes, I believe that it is correct that it was removed from this list.