Hi everyone, I am wondering what code has to go into the controller and what into the model. Generally I would think that all operations that keep the model in a proper state should be done within the model, and the controller should only provide the actions necessary to carry out the application''s use cases. Am I right so far? My situation is the following. Whenever an admin performs the action of creating a new record of questionnaire type (i.e. a new questionnaire for a client), it also needs to create records in the tables storing the questionnaire input data. My first guess was that this functionality should be implemented in the questionnaire model class, as it is the models responsibility to keep itself in a proper state. However, I get an "uninitialized constant" error, when I try to call QuestionnaireInputData.new from within the Questionnaire model class. If I do the same from within the controller, and declare model :questionnaire_input_data then everything works fine. The problem is that in my opinion this pollutes controller code very much, apart from that, it''s simply not the controllers job to perfrom these operations. What I basically need to do is create new instances of othe model classes from within a model class. There must be a way this can be done, right :)? cheers Martin