Schema coordination in federated database management: a comparison with schema integration

We introduced a new approach, termed schema coordination, as an alternative to the well-known schema integration approach for processing cooperative queries in federated database systems. The schema coordination approach is based on the attribute correspondence matrix that links similar attributes in all component databases. In this paper, we compare the schema coordination approach with the schema integration approach for both metadata management and cooperative query processing. We demonstrate that schema coordination ooers a much simpler methodology that enables logical data independence and is especially better suited for database federations consisting of many competing databases with ever-evolving metadata.