1) Defining Relationships and no impact - all it does is to add yet another field and index to your table you put this as a foreign key in related tables and continue as you would with any other relation 2) VFP's default Referential Integrity ( not xcase ) actually this can make your life easier if you are using VFP's RI as VFP's RI doesn't handle compound indexes too well thus in a table that came from a relation (for example a many-to-many link table) instead of using a primary key which is tableA primary+tableB primary (which will cause you trouble with VFP RI) you would use a single surrogate key as the primary of the link table etc. Arnon