Hi guys, Just to get the terminology straight. This thread (and the one on zope3-dev) seems to be using the terms relation and relationship interchangeably, but they're not. A RELATIONSHIP is what we are talking about in this thread: a way to record (and eventually add data to) a link between two potentially different objects, whereas a RELATION is a set of similar objects. Mapping to RDB, a RELATION is a table, whereas a RELATIONSHIP is usually expressed as a join between two tables by the primary key in one of them and a foreing key in the other. In Zope and in Python we already have RELATIONs, by putting a bunch of similar objects in a list or as children of a Folder or ObjectManager. We still don't have a convenient way to express RELATIONSHIPs, and this thread looks very promising in this regard, but the APIs being discussed here are already calling RELATIONSHIPs RELATIONs and this worries me a little. I-only-know-enough-about-this-topic-to-annoy-people'ly yours Leo. -- Ideas don't stay in some minds very long because they don't like solitary confinement.