Federation and stepwise reduction of database

Many enterprises suffer from the problems of heterogeneous data (base) systems, such as redundancy and lack of control. Existing approaches either try to couple the database systems into a federation (FDBS) or migrate data to a single (often new) database system: This paper proposes an integration of both concepts by incorporating migration facilities into an FDBS. General FDBS concepts couple the multiple database systems and allow several degrees of global control over heterogeneity and redundancy. In addition, new migration concepts enable data and applications to move from one component database system to another. This supports the requirement of industrial users to stepwise reduce heterogeneity and redundancy in a controlled way. It allows to decrease the number of database systems as much and as fast as the enterprise areas can bear it