Schema integration and transaction management for multidatabases

Abstract

In this paper we propose a schema integration technique to integrate multiple autonomous database systems. We adopt the unified model, which is basically a relational model with object-oriented features, as the global model for integrating schemas of multiple databases in the relational, hierarchical, network, and object-oriented models. The features and the advantages of the unified model as the global model are discussed, then we describe the methodologies to integrate heterogeneous databases using this model and show how various types of conflicts are resolved. We also show how a global query on the integrated schema is handled in heterogeneous environment. We also present a transaction management scheme which uses semantic recovery techniques. Our scheme does not impose any restrictions on data items that transactions can read and write and does not violate local autonomy.