The Research On Active Rule And Execute Model In Active Database

This paper studied and designed the Knowledge Model and the Excute Model based on the Active Database, combined with the Artificial Intelligence and Object Orient, especially on the Active Rule and the Excute Model.In the aspect of Active Rule ,this paper described a measure of composite event detection based on Colored Petri-net on analysis of the Active Rule. The paper described the definition of the Petri-DS. The place simulated the event and the transition simulated the limitation put on the primitive events to make up of the composite event. Different composite events have different guard expression. Then the paper discussed the implementation of this measure.In the aspect of Excute Model, this paper analyzed usual concurrency control protocol: Two-Phase Locking, Multiversion Concurrency Control and Multiversion Two-phase Locking Protocol, optimized conventional MV2PL protocol ,and provided a transaciton model of Active Database. The model optimized the read-only transaction and the update transaction separately. In the optimization of read-only transaction, we decreased the data consistency, thus the read-only transaction could read newer data versions. In the optimization of update transaction,we added a function to the read operation of active transaction to check whether there existed an uncommited data version. After optimization , read operation could get newer data version than MV2PL.