Much of the current work on model transformations seems essentially operational and executable in nature. Executable descriptions are necessary from the point of view of implementation. But from a conceptual point of view, transformations can also be viewed as descriptive models by stating only the properties a transformation has to fulfill and by omitting execution details. This contribution discusses the view that model transformations can be abstracted as being transformation models. As a simple example for a transformation model, the well-known transformation from the Entity-Relationship model to the Relational model is shown. A transformation model in this contribution is nothing more than an ordinary, simple model, i.e., a UML/MOF class diagram together with OCL constraints. A transformation model may transport syntax and semantics of the described domain. The contribution thus covers two views on transformations: An operational model transformation view and a descriptive transformation model view.