>Hi,
>With binary indexes are you able to create a logical binary index based on the value of a numeric field i.e. IIF(osbalance=0,.F.,.T.) and have rushmore optimize it within a select.
>i.e. Select * from invoice where osbalance=.T.
>
>It would save a lot of space in the index and should be faster as well.

Yes, you can use a binary index in this case. However, you can simplify your index expression a lot.
IIF(osbalance=0,.F.,.T.) can be simplified to osbalance#0, in other words

Index on IIF(osbalance=0,.F.,.T.) tag yourtag && will work, but "overkill"
Index on osbalance#0 tag yourtag && much shorter and faster

The same simplifiation can be used in many cases which many programmers clearly are not aware of.

lValue=.T.
?lValue=.T. && Bad code
?lValue && Good code

Unfortunately youi can not set order to a binary index, but a binary index will be used to optimize queries.