I myself am having problems with a self-referring tree structure of persistent entities where the root element has no parent and I get the exception
org.datanucleus.exceptions.NucleusUserException: Field ....cloud.persistence.ItemCategory.icParent should be able to provide a reference to its parent but the entity does not have a parent. Did you perhaps try to establish an instance of ....ItemCategory as the child of an instance of ....ItemCategory after the child had already been persisted? when attempting to read the root element. Perhaps the DataNucleus plug-in for Google App Engine Issue NÂș 80: "Recursive relation does not work" is the relevant issue (which I have now starred to monitor progress)? --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine for Java" group. To post to this group, send email to google-appengine-java@googlegroups.com To unsubscribe from this group, send email to google-appengine-java+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en -~----------~----~----~----~------~----~------~--~---