Edmond-

>My application hasn’t been designed yet. This data problem is my first hurdle. It will have to be distributed on a single CD, though, so I need to get the data down to no more than 650 MB. If need be I can write a dll with something else like VB or C# if that’s what it takes to get the data down and read it.

I don't understand how that will affect the size of your data store.

> Normally I would look at 6 Gig of data and say there is no way to knock it down to 1/10th it’s size and still have it accessible as live data but since I see that the other vendors have done this, then it must be possible. I just don’t know what format they are putting the data and what language/engine they are using to access it.

I'm short of time today, so can't give a lot of attention to this, but one comment...using the choice of VB or C# are not going to affect your data size, right? They don't have native data engines. The question is: what is the best data backend to use. Your choices are VFP, MSDE, SQL Server, Oracle, DB2, and so on.

Unfortunately, or fortunately, IMO, I get to use the VFP data engine so I can't really recommend which data store will be the most efficient.