School of Information Technology Technical Report 01/2008 Bruchsal, April 2008 ISSN 1861-9231 (print version) ISSN 1861-924X (online version) Dr. Hagen Höpfner is Assistant Professor for Databases and Information Systems at the International University in Germany. Friederike Klan is research assistant at the Friedrich-Schiller-University of Jena. Contact: hagen.hopfner@i-u.de Proceedings of the 20. GI-Workshop on Foundations of Databases (Grundlagen von Datenbanken) May 13 – May 16, 2008, Apolda, Germany Hagen Höpfner (IU Bruchsal, Germany) Friederike Klan (Uni Jena, Germany)