Hi Team, I could not yet get a proper working instance of an object with Database Tree property. Is there any reference I can check on detais of how I can use this? Everything I could find related with DBTree was on JIRA and they're not clear. I see that I need a page hierarchy to display. Is it only a matter of parent-child relationship (if so, how can I inform to DBTree property the "root" of the hierarchy) or I can use the XE's native "relational" mechanism between objetcs, as I do with Database List? I've tested both approaches, without success. I'm not using App within minutes, because I would like to learn and understand how this works to build bigger applications. Below is the example of what I'm trying to build. Thanks again in advance, Ramon Brandão -----Original Message----- From: users [mailto:users-bounces@xwiki.org] in name of Ramon Gomes Brandao Sent on: terça-feira, 24 de novembro de 2015 19:30 To: users(a)xwiki.org Subject: [xwiki-users] Database Tree property Error on XE 7.1.2 Hi Xwiki Team, I'm building an application on XE 7.1.2 and it uses classes with 1:N relations between them through Database List and (potentially) Database Tree property. The relation using Database Tree is not working. For illustration of my use case, I have the following classes: Space.Info0Class with properties: "info0ID" type String "info0Name" type String Space.Info1Class with properties: "info1ID" type String "info1Name" type String "relatedInfo0" type Database List -> with Xwiki Class Name=Space.Info0Class, Id Field Name=info0ID and Value Field Name=info0Name Space.Info2Class with properties: "info2ID" type String "info2Name" type String "relatedInfo1" type Database Tree List -> with Xwiki Class Name=Space.Info1Class, Id Field Name=info1ID, Value Field Name=info1Name and Parent Field Name=relatedInfo0 The relation I want to build is, then: 1 Instance of Info0Class can be related to (0...N) Info1Class, which then can be related to (0...N) Info2Class. When creating a new instance of Info2Class, I would like to show the information on relatedInfo1's select box in a tree view manner, where the "relatedInfo0" instance name is the aggregator and all the related Info1Class instances are the leafs. Thus, the user can get a much better idea of which Info1Class she/he can select for relatedInfo1 field. I've used, since then, only the default pages and codes generated by class editor (default sheet to display class properties and default template). I got the relation working like a charm between Info1Class and Info0Class, but things are not working with Info2Class and Info1Class. Creating a new instance of Info2Class triggers a "org.apache.velocity.exception.MethodInvocationException: Invocation of method 'display' in class com.xpn.xwiki.api.Document threw exception java.lang.StackOverflowError" and infinite "com.xpn.xwiki.objects.classes.DBTreeListClass.addToSelect(DBTreeListClass.java:319)" calls. In this way, I could not even check if this use case is valid for the Database Tree List. I've searched deeply and really could not find any further documentation about Database Tree Usage, neither examples, nor detailed information on how to get this working. The only reference is a brief description on the XWiki Data Model Page mentioning the Yahoo Javascript Tree Library. So, the questions for the team are: 1) Where can I find more information (a good tutorial/documentation/usage example) about Database Tree List? 2) Is it suitable for this use case? Am I doing it right? 3) What do I need to get a Database Tree property/relation to work? Thanks in advance for your help. Best Regards, Ramon Brandão _______________________________________________ users mailing list users(a)xwiki.org http://lists.xwiki.org/mailman/listinfo/users