I'm doing this right now..it's really quite simple.
The trick is to make sure that your VFP data-types in your tables will work in SQL Server. For example..use DateTime fields, not Date, not Time.
Next - connect to your VFP database with ODBC Driver and querry it STRICTLY with remote views and maybe some sql passthough.
Now - want to access SQL database with same code? No problem change the connection string for the remote views and yer done. Takes all of like 2 seconds.

>While researching what is involved to upsize/migrate our application to use a SQL Server back end, I recalled that that my colleague wanted to achieve having a single set of code that supported the use of either SQL or VFP as the data engine (depending on the client site). I think the reasoning for this is because we cannot anticipate all of our clients wanting to migrate to the SQL version at the same time.
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>I was curious if anyone here has had experiences (be they good or bad) in the scenario described above. Are we looking for headaches?
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>Any insight would be greatly appreciated.
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>Laterness,
>Jon