Making an object-oriented database active
Yue Dong, Angela Goh · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1996
One key technology required by a CAD/CAM is a database system management. However, conventional database systems are not well suited for CAD/CAM applications because of their lack of support for complex structured data and their inability to meet the demands of dynamic changes of schemas. Object-Oriented Database systems have many advantages over conventional database systems, such as the ability to support complex objects and long transactions in CAD/CAM. The main feature of an Active Database is to react autonomously (without user intervention or application request) to events that can occur in a database. An active OODB system will meet requirements of a wide range of applications, in particular, for CAD/CAM systems. In this paper, we propose a layered architecture to represent an active OODB by putting an active facility on top of a passive OODB system. In this active layer, we use a rule/event interface to specify rules/events and to store rules/events as `first-class' objects which can be created, inquired, deleted and updated like other objects. In this paper, we will focus on the specification of expressive ECA (Event-Condition-Action) rules, detection of primitive and composite events. Finally, we will discuss how to implement the architecture using a commercial OODB such as ObjectStore.