title: how can i update an object/entity that is not completely filled out?
body: <p>I have an entity with several fields, but on one view i want to only edit one of the fields. for example... I have a user entity, user has, id, name, address, username, pwd, and so on. on one of the views i want to be able to change the pwd(and only the pwd). so the view only knows of the id and sends the pwd. I want to update my entity without loading the rest of the fields(there are many many more) and changing the one pwd field and then saving them ALL back to the database. has anyone tried this. or know where i can look. all help is greatly appreciated.</p>
  
  <p>Thx in advance. </p>
  
  <p>PS
  i should have given more detail. im using hibernate, roo is creating my entities. I agree that each view should have its own entity, problem is, im only building controllers, everything was done before. we were finders from the service layer, but we wanted to use some other finders, they seemed to not be accessible through the service layer, the decision was made to blow away the service layer and just interact with the entities directly (through the finders), the <code>UserService.update(user)</code> is no longer an option. i have recently found a <code>User.persist()</code> and a <code>User.merge()</code>, does the merge update all the fields on the object or only the ones that are not null, or if i want one to now be null how would it know the difference?</p>