Within the scope of this thesis bidirectional XML-Middleware for database systems and its functionality for data transformation was analysed. Bidirectional middleware enables data transformation from databases into XML-documents and vice-versa.

After the evaluation of several middleware, two of them with different kind of mappings fulfilled the desired criteria and were further analysed. One middleware for relational database systems was chosen and integrated in a prototype.

The prototype was developed in Java. It demonstrates the features of the chosen middleware. In order to allow a simple handling of this prototype, a user-friendly graphical user interface was implemented. The Prototype was realized as a Java-Applet in order to be executed on a WWW-Browser. By using the JDBC-interface to access a database the prototype is independent from any specific database system.