>To enforce the relationships, just use the referential integrity builder that comes with Visual FoxPro, or an alternative RI-builder.

>Whether you use primary keys made up of a single field or composite keys, the relationship is from one index to another index. It works exactly the same way.

I was indeed confused, probably because of my ignorance of the VFP database. I thought that creating a relationship from one index to another was already enforcing data integrity. I have to read some more documentation !