DESIGN AND IMPLEMENTATION OF A GLOBAL DATA MANAGER

Abstract

In spite of rapid advancements in the development of communication networks, there is still a great need for the development of improved communication between remote, database management systems, or DBMSs. At present the lack of effective communication between distributed DBMSs is primarily due to the significant differences between local data managers, local data models and representations, and local transaction managers. The interconnection of remote DBMSs fundamentally requires the user to have an easy, uniform and integrated access to remote data without letting him know the underlying differences. The solution to this problem requires a well define set of goals to be clearly specified. On the lines of these goals, Gray has given an architectural -►ode1 to extend the features of existing centralized DBMSs to accomodate distributed systems and networks. In this model, the application layer is divided into three sublayers; each performing a well defined function. The topmost sublayer is the Global Data Manager of the GDM, which aims at achieving the transparency of the local DBMS. It interacts with the user and process their queries at the most global level. To accomplish this, it maintains a global data model and a unified data dictionary which defines global user view of all the data and the conflicts, if exist, in the local data models. In this dissertation; an attempt has been made to observe some of the features of the global data manager.