Shall we persistent all the objects mentioned in Domain Model? In other word, shall we introdue all the classes in the Domain Model diagram into the Class diagram that we need to create?
Really, I think you have to look at the system requirements. Do they ask you to store every field persistently, for every object in your domain model? If so, the answer is yes. If you don't need to persist every field in every object, then the answer is no.
My gut instinct would be "No", but each assignment is different. It does seem like overkill to persist everything, doesn't it?