Hello Sally, that is correct, that classes without any behaviour is not good designed. But my intention is, that you can use this classes of data for building classes with behavior. Additionally, you can use the data class model for defining tables in a OO-based or XML-based database. For that definition is a behavior of classes not necessary. I started with that definition of seamless integration between object model and data model. After my first tests is my feeling that it works. Kind regards Gunther