changed: - I just got the structure of the existing PDB please see [PDB Mysql Struture Dump] which should be converted to the Plone Interface: I made a UML diagramm how it could work: One thing is that we combine all tables of externals, patches, abstraction to one and put in an selection from a Vocabulary which is administrated with The Vocabulary Manager. The other thing is I dropped the table URLS, instead there is an entry URL which can be used in the entries or be superceded by the Library URL. Anyway I dont know what todo with the Persons... but see yourself.... The UML diagrams I made and the Product autogenerated where the model is included. I used Poseidon UML 3.0 from http://gentleware.de/ community, since it seems to work best, but its a monster... Here is the Zope Product autogenerated with the modelfile included: <a href="PDDatabase.tgz">PDDatabase.tgz</a> The graphics: <img src="TypeDiagram.png" /> <img src="VocabulariesDiagram.jpg" /> <img src="TypeDiagram.jpg" />