Just one point. The concept of abstraction to enable any SQL compatible RDBMS makes perfect sense, to a rigorously OO way of thinking. Ironically, strict adherance can sometimes lead down a path where a truly marvelous option is dismissed, simply because it is unique. The objects to be stored are, after all, objects, not data fields. The shortcomings of FileStorage are limitations related to heavy writes, and non-atomic undo. Other aspects have proven very appropriate for the task of enabling persistence in objects. The inherent features of PostgreSQL to allow user defined, inheritable datatypes, suggests remarkable synergies with the intention of the proposed DB Storage, if not with every stated goal. It seems a shame to ignore this possibility just because Oracle / MySQL have so much mindshare. When such a tool exists that excels at storing objects, in a tabular sort of way, should it's special talents be disregarded just to avoid overdependence on an incomparably suitable solution? In the worst case, perhaps a PostgreSQL implementation of a Rack could be expected to directly handle aspects of Object Persistence that must be supplemented with Property Sheets, etc. in alternate implementations. Just in case a Zope newbie is reading this, and hasn't heard of PostgreSQL before, it is also Open Source. http://www.postgresql.org Later, Jerry S.