A universal relation approach to federated database management

We describe a manufacturing environment where, driven by market forces, organizations cooperate as well as compete with one another. We argue that a federated database system (FDBS) is appropriate for such an environment. Contrary to conventional wisdom, complete transparency, assumed desirable and mandatory in distributed database systems, is neither desirable nor feasible in this environment. We propose a new approach that is based on schema coordination rather than integration under which each component database is free to change its data structure, attribute naming, and data semantics. A federated metadata model based on the notion of universal relation is introduced for the FDBS. We also develop the query processing paradigm, and present procedures for query transformation and heterogeneity resolution