Integration of object-oriented and relational database systems

In an organisation, there are many autonomous database systems with different data models, query languages, and schémas. The user in the organisational level needs to have a shared access to the databases by using a single data model, and a single query language. The aim of this thesis is to propose and evaluate a method for integration of autonomous, heterogeneous database management systems ODBMSs) to facilitate shared access through a system, based on the method, called Database Integration Methodology (DIM). The thesis first reviews the basic concepts as related to heterogeneous DBMSs^ then DIM is proposed as a general method for integration of a number of heterogeneous DBMSs. A DIM system has one unified data model to give a homogeneous view of the databases to the user. It has also a database query language for retrieving and manipulating data from the databases. We present a method and explain through it, how a translated query language statement of a DIM system which is a set of query language statements of local database systems, is combined to make a shared access to the databases possible. As one particular case of the general method, DIM is implemented for integration of object-oriented and relational DBMSs. We choose relational data model as the unified data model of the DIM. A solution for translation of object-oriented schémas into relational schémas is considered.