Object-oriented database management systems (OODBMS) are used to imple- ment and maintain large object databases on persistent storage. Regardless whether the underlying database model follows the object-oriented, the rela- tional or the object-relational paradigm, a key feature of any DBMS product is content based access to data sets. On the one hand this feature provides user-friendly query interfaces based on predicates to describe the desired data. On the other hand it poses challenging questions regarding DBMS design and implementation as well as the application development process on...