usually you have one remote rmi server. It serves objects from the remote databse. Once recieved these objects have no connection to the remote data.
Another way is to have the rmi server serve you objects that are still connected to the remote data. This is done via a "Factory". In effect every object you recieve from the factory is bound in the registry and is in itself a rmi server. A "toString()" from this object would then reflect the data currently on the server and not only local changes. changes to this object would also change the remote objects state.
If you track references handed out to the objects and also "return them" by some method before disposing them, they could also be unbound when they are not referenced any more. It is described in detail in [W.Grosso,"Java RMI", O'Reilley, 2002, pp.377-382]