>Thank you. The SQL Server is so fast that I could not see if my index was used or not (after I added it in the SSMS). But of course I am running it on the same computer where the VFP app resides so it is not a real-life case.

Speed depends. Yesterday I had to zap one big table, 2.5 million records, and it doesn't really zap it, it deletes all - took 30 minutes. I could see the record count dropping (using Toad, of course, it's just a F5 to refresh the table properties pane; in SSMS it's three clicks and the fourth to close the dialog, because it can't refresh).