Ehm, I would think that unless person implements a PropertyChangeListener, you need to tell the engine about the change of the slot. Update would be the proper way AFAIK. In this case, I don't see why one would want to insert an object into WM - as it is already in WM. I think the exact result of the insert depends on whether you have implemented equals/hashCode properly. But again, in that example I understand that you want to change the property of an object you have matched in the LHS. The way to do this is using update(). -- Ingomar Am 11.09.2008 um 12:39 schrieb Shyam, Pallav (MSCIBARRA):

What version of Drools are you using? Pre-5 has "Shadow Facts" so you can't rely upon pass-by-reference. I believe 5 has had Shadow Facts removed. Insert places a new object into WM whereas update refreshes (the shadow) of an existing one. I would expect you to have to use update in your example:- rule "Add person to math class" no-loop when person : Person(likesMath == true) then person.setClassName("Math"); update(person); end rule "And now, time for something completely different" no-loop when person : Person(likesMath == true) then PreferredClass p = new PreferredClass("Math"); p.setPerson(person); insert(p); end Cheers, Mike ________________________________ From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Shyam, Pallav (MSCIBARRA) Sent: 11 September 2008 11:40 To: rules-users(a)lists.jboss.org Subject: Re: [rules-users] Update vs insert Very strange. The facts are passed into the WM by-reference. Therefore the query should work after calling the person.setClassName("Math") on the fact. And this should work without calling the insert or update. This leaves me guessing that the query does not work on the facts directly, instead they work on shadow facts. ________________________________ From: rules-users-bounces(a)lists.jboss.org To: Rules Users List Sent: Thu Sep 11 04:41:37 2008 Subject: [rules-users] Update vs insert Hello, What is the difference between calling insert and update in a rule file? When I use insert my queries don't work, but if I use update they seem to. I don't mind using update, but I would like to understand the difference between the two. Here is my rule file. rule "Add person to math class" no-loop when person : Person(likesMath == true) then person.setClassName("Math"); insert(person); end I also have a query: query getPeopleForClass(String _className) Person(className == _className) end When I add two facts to working memory, where the likesMath attribute is true, then run my query I get zero results back. When I change the rule, "Add person to math class", to use update(person) instead of insert(person) two students are returned. Any help would be appreciated. Thanks, Dan Daniel Quinn Fedex - Custom Critical Software Specialist I 234.310.4090(x2586) -----Original Message----- From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org <mailto:rules-users-bounces@lists.jboss.org> ] On Behalf Of thomaskukofka(a)web.de Sent: Wednesday, September 10, 2008 2:27 PM To: rules-users(a)lists.jboss.org Subject: [rules-users] Re: looping problem Hello, thanks that works. I just forgot to set the focus in the init rule.. Regards Thomas _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users <https://lists.jboss.org/mailman/listinfo/rules-users> ________________________________ NOTICE: If received in error, please destroy and notify sender. Sender does not intend to waive confidentiality or privilege. Use of this email is prohibited when received in error.