Extending the Object-Oriented Database Management System VODAK with ActiveCapabilities

摘要

The development of object-oriented database systems means a great advance innarrowing the semantic gap between the real-world representation and the database representation of objects. But, object-oriented database systems are passive, they contain objects that do not act autonomously on predefined situations. This weakness of passive object-oriented database systems becomes apparent in situations, where database states have to be monitored. Within this thesis, the distributed object-oriented database system VODAK, is extended with active capabilities using the concept of event-condition-action (ECA) rules. Besides conventional application classes and metaclasses, an Active VODAK database contains rules which define situations to be observed and actions to be initiated. Rules and rule components (events, conditions, and actions) are treated as first-class objects; they represent a homogenous extension of the VODAK data model. Besides questions of integrating rules into the VODAK data model, diverse aspects of rule execution are considered and architectural issues are discussed.