A Multidatabase System as 4-Tiered Client-Server Distributed Heterogeneous Database System

In this paper, we describe a multidatabase system as 4-tiered Client-Server DBMS architectures. We discuss their functional components and provide an overview of their performance characteristics. The first component of this proposed system is a web-based interface or Graphical User Interface, which resides on top of the Client Application Program, the second component of the system is a client Application program running in an application server, which resides on top of the Global Database Management System, the third component of the system is a Global Database Management System and global schema of the multidatabase system server, which resides on top of the distributed heterogeneous local component database system servers, and the fourth component is remote heterogeneous local component database system servers. Transaction submitted from client interface to a multidatabase system server through an application server will be decomposed into a set of sub queries and will be executed at various remote heterogeneous local component database servers and also in case of information retrieval all sub queries will be composed and will get back results to the end users. KeywordsDistributed Databases, Multidatabase, 3-tiered Client-Server system, Schema Transformation, Schema Integration.