Here is a good solution for VFP by Andy Kramek. It's well worth a look - Andy loves his data ! :)

http://tightlinecomputers.com/Documents/DataClass.zip

>Hi.
>I am loking for poninters on design methododology .
>
>On my next main App, my preference is to design the system so that the end user can select the Underlying database, whether this is Visual Foxpro, Sql Server ,Access, MSDE or say Oracle,
>
>The reasons for this are many:-
> Cost (e.g VFP is free, Msde is free but limited by users
> Interoperability with other modules
> Corporate requirements (e..g. Some companied insist on Sql Server
> Security (Perception is out there that some Databses are more secure
> than others)
>
>Because of these various considerations, I see a lot of merit in the ability to design a 'Generic' system but being able to 'Depoly' it using a specific choice in Database.
>
>
>Ideally, I would like to program the app in a language which will allow this.
>I have no hangups ,at this stage, as to wheteher the language is VFP, Visual studio, C Sharp or Visual basic or a.n.other
>
>My main concern is that I can, by means of a one paramter setting, specify the underlying database. I dont want to have to make any changes whatsoever to the code:
>
>I would apprciate feedback on thisorm the VFP community, and have 3 specific questions:
>
>1. Is this Utopia.. or is is possible ?
>
>2. Has this already been done ?
>
>3. What is the best language to achiive this ?
>
>Thanks in advance for any contributions to this topic.
>
>regards,
>
>Gerard