Hi everyone, I was a Java addict until I discovered Python and Zope. I am just getting into Zope, trying to put together a contact manager app as an exercise. I have a few questions: a) The contact manager will hold information for contacts(people) within organizations(companies); organizations will be categorized by predefined industries, etc. I am not sure how to model this; I am still a bit confused about how to approach a problem in Zope; it's so different... My first idea was this: - Create an 'Organization' ZClass, in which there is a 'Contact' ZClass - Create an 'Industry' ZClass Then: - Create an 'Organizations' folder (contains Organization instances) - Create an 'Industry' folder (contains Industry instances) Now, my question is this: how do I relate an organization instance to an industry instance? How do I materialize that possibility through the UI - I mean, how do I show the different industries in a listbox in the Organization's create/update screens? I am still quite confused about how objects in given folders have access to objects in other folders. Could someone help me on this - an example may be? b) Objects, references and ZODB Suppose I successfuly assign an industry object to an organization object, how is that persisted in ZODB? I mean, does the organization object only keep a persistent reference to the industry object, or does it copy the industry object entirely? What is the proper way to handle such cases in Zope? c) "mutable sub-objects should be treated immutably" - from a ZODB point of view. I am not sure I completely understand this (I understand mutable and immutable allright, but I do not see what makes a mutable object being treated immutably, and how/why it affects ZODB). Yanick yduchesne@zdnetonebox.com :) ___________________________________________________________________ To get your own FREE ZDNet Onebox - FREE voicemail, email, and fax, all in one place - sign up today at http://www.zdnetonebox.com