The Parallel Execution Of The Nested Transaction In Active Database

To aim at a series of problems in composite event detection, concurrent control of nested transaction, specification language of rule and the cooperation of the component, the method of integration of parameter contexts based on global event history and the idea of extended nested transaction model in HiPAC system are proposed through the research on the parameter contexts and the global event history. At first the rules specification language is introduced. And after the basic knowledge about the active database, the paper introduces the parameter contexts based on global history to detect the composite event. Then the paper tries to make it clear how the rules are stored in active database. After that, the extended nested transaction model is introduced to deal with concurrent control of the rules.The model improved the performance of active database effectively.On the base of analysis of HiPAC system, the paper discusses the characteristic of the system and puts forward a method of optimization. This method is to put a global event detector into rule manager which is used to detect global event history. And at the same time a dimension is added to each rule's event part in the rule manager. It realizes the detection and control of the composite event usefully by using this method.