To support complex queries in OO.org base, one can use views. The problem is that the views are not updateable even if the database is set up with triggers in place so that if you try to actually INSERT, UPDATE or DELETE on the view, it succeeds.

As a kludgey workaround, I've been using writable materialized views. They are physical tables, with primary keys (so that OO.org base allows updates), with a set of triggers that bidirectionally keep them in sync with source tables.

It would seem that the only information missing from OO.org base to support writeable views is the set of columns to be used for primary keys. Setting this on a view should enable modification of said view. This would remove the need for the writeable materialized views workaround.