Martin,

psSQLFilter set in a parent DDO is not going to work. It is not used. The reason for that is that you always find a particular row and use the relate mechanism to load the parent row.

What you can do is use the Constraint mechanism for that.

psSQLFilter is not a replacement for constraints. It is a helper for the SQL database engine to improve the find operation. Many constraints are automatically translated in SQL where clauses.