Multi-column indexes vs Single Column Indexes

I am using Orale9i and Oracle 10g on Windows and UNIX boxes. When creating new indexes which are non-unique, what are the pros and cons of creating a single index of multiple columns vs creating a separate index on each column.

For example, if I created separate indexes: one on col1 and other on col2,
Oracle could use these indexes if either col1 or col2 was used in queries.
However if I had an index on multiple columns (co1, col2), Oracle will not use
Index if query used only col2. I know in Oracle9i, Oracle can use parts of multi-column index for col2, but this is not as efficient as having a separate index on col2. Disk space is not an issue for me, so I will be better off using a separate index for each column.

Thanks Received on Sat Aug 11 2007 - 20:50:57 CDT