HETEROGENEOUS SCHEMA INTEGRATION METHOD FOR MULTIDATABASE SYSTEM

Abstract

In this paper, we propose a view class, a view hierarchy, and an integrated view schema for heterogeneous schema integration on the basis of an object-oriented data model. Heterogeneous schema integration aims to integrate different types of local schemas. which may be written in different data models or may be designed independently, into an integrated schema for sharing information on a global basis. All semantic relationships among the local schemas are allowed to be represented in our schema integration method while alleviating integration overhead in comparison with the traditional approaches. The view class is able to represent all semantic relationships between the pre-existing classes(or base classes). A view class is defined by a query and can be a base class of the other view class. The view hierarchy represents IS-BASIS-OF relationships between a view class and the base classes underlying the view class. The view schema consists of the class hierarchy, the composite class hierarchy, and the view hierarchy. Within the view schema, an application is allowed to access the local databases on a global basis. A view schema can be integrated in two phases. The first phase is to transform each local schema of local database into an object-oriented local schema. The second one is to integrate the transformed object-oriented local schemas into an integrated view schema.