>>We are planning to rewrite a VFP application which uses DBFs to .NET and SQL Server. The system is extremely large and is comprised of a large number of subsystems invoked from a main PRG and menu. It is not considered feasible to convert everything at once. Instead the plan is to rewrite a piece at a time as resources and budget become available. Has anyone done something like this? To me it seems like the data is going to have to reside in both VFP and SQL Server until everything is converted. Any tips on good ways to do that?
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>>Rewriting a piece at a time can be difficult, if the existing application is also evolving.
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>>Has the team defined segments/timelines for each piece and what will be included? What kind of timeline are you talking about?
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>>Do you have a dedicated QA team? They can be a big help during the transition phase... (just a more general question, what's the size of the team)
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>Thanks for the advice. Most of that is not within my control. For at least a couple of reasons the decision was made (above my level) that we can only do it a piece at a time. I have been asked for advice on the data migration strategy so that is what I am concerned with.

My advice : resign now. If the aim is to migrate piecemeal from a purely VFP app to a .NET/SQL implementation then all you end up with (if you are lucky) is a pigs-ear .NET application emulating how it was done in VFP. Even without knowing the ins-and-outs of the application involved I'm sure that, in the end, it would be far more efficient (and result in a better application) to start the .NET effort from scratch.
My 2c