>So, how do you know which field is the primary key? Isn't this need in the CA to be able to update the backend from the cursor changes?

Yes you do. There is code in the builder to populate that property as well. It works perfectly for Oracle and SQL Server. It does work for VFP DBCs as well, however, if the PK contains a function, you will have to tweak that property. There is no easy way to get this in VFP. If it contains multiple fields, you will probably have to tweak that as well. But at least I put the PK index expression in the KeyFieldList property [actually this is done via code in the INIT] so you can have something to work with.