Robert, <opinion> I was tossing that same problem around before I said yes to the Catalog and ZClasses. I went with the them because the structure I have is mostly Hirearchicle in nature. I do however have two objects that store a referring object's id as a property. I have submission objects that contain a reference to a person object that was sent. I do a DTML _.getattr(_.getitem()) call to get the piece of the person object I want to grab in reference to that submission, or a (off the top of my head untested ) <!--#if person--> <!--#with People_Folder--> <!--#var "_[_['person']]"--> <!--#/with--> <!--#/if--> and that renders the actual document stored in the person property.(I have gloablly unique id's for ZClass instances) That's all fine and good, it can be done, but when you delete the object stored in that property, Zope will not be able to find it, true, and ugly. I thought of two ways to check that effect a) write DTML to display only if the id is valid b) write a method that takes place when you delete a ZClass instance that does a quick Catalog search and update that replaces it with whatever value you want. Even ORACLE 8 has to clean up after itself in this way if you use its new REF sql construct. But they wrote it so you have to pay for it and don't even know what it does. Funny thing is that if you are keeping around old copies of something that refers to objects that no longer exsist, the instance itself no longer has to be dynamic, it is history. So preserving thier dynamic nature does nothing for you. The Order Class is only applicable when it's dynamic, and a subclass or whatever, more accurately depicts the order after the purchase has cleared and can't change anymore. After paid, then the order ceases to be an Dynamic Order and becomes a Static Order. Static orders could just be a DTML method with some proerties. It's history. You're only keeping it around so that you can say who bought what when, etc... This is all just the way that I did things here, and it probably only applies to me, but I thought I'd give my thoughts such as they are. To be honest, I'd contort my ususal way of doing things just to have the speed, ease of use, flexibility, and extendability the Zope offers. I weighed all the possibilities on the scale of Web Applications and Zope came out the winner. Everyone has thier own scales. </long, way too long, opinion>;-) All my best, -- Jason Spisak webmaster@mtear.com