Bruce,
The table on the browse is the 'link' table of three related tables.
So I have four tables:
-RegistratieVraagAntwoord (RegistratieId,VraagId,AntwoordId)
-Registratie
-Vraag
-Antwoord
As answer to your question: the RVAUniqueKey contains VraagId and AntwoordId, but I have forgotten to put RegistratieId in there as well, since combination VraagId and AntwoordId could possibly already have occurred.
Thanks for shining this light