RE: [Zope] Will the inheritance relationship will be preserved after export/import?By stealing some codes from AlexR's helpful how-to "Changing Base Classes for a ZClass". I wrote an external method to be a quick-and-dirty work around. (see the attachment) This external method helps a zclass to change the old reference of its base class (an instance of ZClass) to the new one in "new" ZODB. Just install this external method(with t,t,t as parameters) and request it by a browser. It will response a form for you to fill in your product/class name pair. "Source Product/Class" is for the base class. "Destination Product/Class" is for the class which lost its reference to the base class. The value of class accepts nested class which means ClassA/ClassB/ClassC.... is valid for this field. In my own case, I have a nested class up to 5 level. The "replace" field is for inputing the index of the old reference of base class which is going to be replaced. (starts from 0) Since the base classes is an array which is a mixup of serveral products. The "copy" checkbox is for doing a full-replacement of base classes from source zclass to destination zclass exactly as what AlexR's script does. The "Test Run" button won't do the real task. It just gives the information of what is going to happen. Use this to dump out the array of base classes of your source zclass and destination zclass. The "Real Run" button will do the real task to replace or to copy. Hope that you won't be regret after hit this button. Hitting "Test Run" is strongly recommended before hitting "Real Run". If the path of source zclass or destination zclass is wrong which means there is no such zclass existed, this external method will response "None" for your attention. Make sure the zclasses you want to operate to are really existed in your ZODB. Most important of all: use it in your own risk. Remember to export your product for backing up before any actions. It works for me not necessary work for you. But I do hope it helps. kosh@aesaeion.com is right. This problem won't be happened in a product which is implemented in pure python scripts. That is quite trivial after dumping the base classes of a ZClasses-based product. Zope is great! Well, I agree with what kosh said "Zclasses are not robust solutions they mostly seem designed for trivial solutions by largely non programmers." Regards, Iap, Singuan