[DavidZ]

I agree that the major problem with using import ids as your primary key for constituents is that you cannot look them up in the same way as you can with constituent ids. One organisation that I worked with used the SSN field (NiN in UK) as the field that linked their two systems. That way they were able to look up the constituent from the search screen. The problem with that of course is the same as the constituent id. It could be changed and removed.

If you did want to go down that route (and have the VBA module) then a simple VBA routine could check that the value has not been changed.

That being said if you do not already own the VBA module I would not buy it just for that one control and would use the import id as you have outlined.

David