Nick,

>In your case you may create IDX indexes which will not touch your table format in any way:
>
>INDEX ON custid TO cistid.idx COMPACT

But then he will have to rebuild the index every time he uses the view in case the DOS app has changed something or added records -- or he will have to change the DOS app to maintain that .idx.

That's why I recommended the index tag approach to create a structural .CDX that will be auto-maintained without changes to the DOS app (unless of course it is an old-enough version that it doesn't support CDX's).