Role of Delegation and Inheritance in Object-Oriented Database Systems

摘要

Research in the field of Computer Aided Design (CAD) is often directed towardsthe use of artificial intelligence and logic programming techniques. For instance, the use of backward and forward reasoning, reasoning with uncertainty and default reasoning. Research directed towards the object oriented paradigm is being developed. It focuses on the development of CAD systems with respect to: the evolutionary character of the design process; the parallel exploration of possible solutions of the design; and the integration of knowledge of other domains during the design process. Inheritance and delegation, two communication concepts between objects, are believed to be important mechanisms for representing CAD information subjected to the above mentioned issues. Although both mechanisms address the same goal, delegation is believed to better suit the requirements of design support. Both mechanisms are already implemented in many systems. However, the objects and their relationships are maintained in main memory and are not supported by a secondary storage device. A database management system which is based on the use of these inheritances and delegations is being developed. With these mechanisms it is expected that more complex structured information and knowledge about design processes and designed artifacts can be stored and maintained. The conceptual differences between both mechanisms are explained as well as some of their implementational issues.