For every “Car Model”, you create a list of Car Versions that it provides. Create a LIST OF property that enables the user to enter Car Versions in the “Car Model” definition. Note that Car Versions is a definition type with a compound key: when you the “Car Version”, you must specify the “Car Version”, and the “Car Brand” and the “Car Model” of the “Car Version”.

There is a problem with the USRPROPS.TXT above. “Car Version” is a compound-key definition: it has its own name as a key, and it has two other key properties, “Car Brand” and “Car Model”. If you specify the USPROPS.TXT above, it will be up to the user to know this. They have to type the “Car Version”, fully qualified by its Brand and Model, with a period separating each, for example: