The Active Mechanism Of Real-time Active Database System ATRs-EDB

Real-time database system is a new database system that that combines the traditional real-time database system and the real-time system.Transactions and data must have an explicit time limits and timing characteristics in the real-time database system. The active mechanism is introduced into the real-time database systems, so that real-time database systems have the active service capabilities which means that system can switch automatically according to system's current state.Based on ARTs-EDB which is an active and real-time DBMS, research in this paper is mainly about the active mechanism supporting ARTs-EDB.With respect to the characters of Real-Time Active Database,the architecture of the system and the architecture of the active mechanism of the system are introduced.The architecture showed the primary modules of the active mechanism.Event is the source of the active mechanism. Introduced the concept of event and the event role and event granularity of the event definition. Then organized the events library according to the type of events. Focused on the detection and process strategies of different types of events.The trigger is the key of active mechanism.Presented the organization of the library and the implementation model of triggers. Then researched on recursive trigger and exception handling as well as relevant processed strategies. Finally, the paper focused on the conditions and evaluation strategies of triggers.The active rules' termination of ARTs-EDB is studied.Test the active mechanism module that can prove the implement of the active mechanism in ARTs-EDB.