Hi, after some playing with Zope i now have to implement my first project, a knowledge base. It is a variation of The KnowledgeKit Product from Bill Anderson (a very good starting point). One change i made to the KBEntry ZClass property sheet 'properties' is using the Notes property as a field for adding links to other KnowledgeBaseEntries (i changed it to type 'lines'). I enter the 'id' of another KnowledgeBaseEntry and in the index_html method of the KBEntry i included the following snippet to create an link to this KnowledgeBaseEntry. -----------KBEntry, index_html --------------- <dtml-if Notes> <tr><td VALIGN="TOP"> <p> <b>Siehe auch:</b> </td><td> <dtml-in Notes> <dtml-if sequence-item> <dtml-let num=sequence-item> <dtml-in "kbCatalog(meta_type='Knowledge Base Entry',id=num)"> <a href='/<dtml-var "kbCatalog.getpath(data_record_id_)">'> <dtml-if title><dtml-var title></a><br></dtml-if> </dtml-in> </dtml-let> </dtml-if> </dtml-in> </td></tr> </dtml-if> ------------------------ kbCatalog is a ZCatalog on all Knowledge Base Entries. This is working well, but there is another requirement to implement. If i add a "link id" in one Knowledge Base Entry it should automagically appear as a backlink in the Notes property of the linked Knowledge Base Entry. And of course if i delete a "link id" it should delete the backlink. Any ideas how i can add this to a KBEntry_change method? Jochen