Check out acs-kernel/sql/[PG/Oracle]/acs-relationships-create.sql
So it looks like a relationship is an entity. Whew. OK. Should I subtype acs-relationship with gr_ratings? If so I guess the relationship would be called rated with user on one side and some object on the other. date_rated and dimension_id wouldn't be part of that relationship. Problem is dimension_id will figure into most queries. Is this a problem?