User - defined Container Basic Object Default

1 Abstract Computerized databases are essential and inseparable components of a vast majority of today's information systems. Database systems are used at all levels of management, research and production to provide uniform access and control of consistent information. Computer aided software engineering system require extensive database system support. Several industrial and academic research and development projects attempt to provide this support by using conventional database management systems or special purpose data managers. Object-oriented database management system technology provides a set of capabilities which are required by computer integrated software engineering systems. Our objective is to take advantage of this new technology and develop computer integrated software engineering systems that support complete user-deened life cycles with uniform interface and logical centralized database support. This paper presents Objectivity (DEC Object/DB) in relation to its architectural issues and shows how applications can be developed by the help of C++ interface. A data model is a logical organization of objects (entities), constraints on them, and relationships among objects in a given application. Just as relational database system is a database system which implements the relational model of data, a object-oriented database system(OODBS) is a system which directly supports the an object-oriented data model 1, 2, 3]. An object-oriented data model is a data model which captures the semantics of object-oriented concepts. Information models are described in Structured Analysis with the Entity-Relationship (ER) formalism 4] and in Object-Oriented Analysis with the Class-Relationship (CR) formalism 5, 6]. The elds of object-oriented programming languages, artiicial intelligence, software engineering, data abstraction and complex data management have all contributed to the development and use of object-oriented technology in the database area. The applied areas that have necessitated OODBS capabilities are-ECAD (electronic computer-aided design), MCAD(mechanical computer-aided software engineering), CASE(computer-aided software engineering), CAP(computer-aided publishing), CIM(computer-integrated manufacturing), Multimedia, Telecommunications, Control systems etc. An OODBS in addition to the object-oriented programming language has three additional features 7, 8, 9]: persistence (objects may live longer than the process that created them, transaction (lumps one or more actions into a single atomic action) and sharing. Several object-oriented database system (OODBS) have been developed like ORION, ObServer/ENCORE, Gemstone, ONTOS, ObjectStore, Versant, Vbase etc. A comparison for some of the above database can be seen from 10, 11]. DEC Object/DB is a family of OODBS which has been designed to be implemented in the object-oriented and distributed systems. It is suitable for applications involving complex data and …