It seems to be a bug. I have the a similar problem in a other table. The workaround that I use now. I call anonymous wrote : createNativeQuery instead of anonymous wrote : createQuery or anonymous wrote : find of the anonymous wrote : EntityManager. The consequence is the field is not set to null. Because I need only one field I don't have to return a hibernate entity object. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3970044#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...