Unfortunately, it sounds as if you are taking an overly-simplistic view here.

A bitmap index in isolation is a waste.

First, you need to know if you have an OLTP or a DSS database. If OLTP, as others have emphasized - NO BITMAPS!!!!! Period.

Conversely, if you are DSS, then you should probably have LOTS of bitmaps. Bitmaps not only work better on low selectivity columns, they work better in groups.

Here is a thread where jurij and I discuss bitmap indexes in start schemas - this is applicable for most DSS situations in general, however.

http://www.dbasupport.com/forums/sho...threadid=11745

- Chris