Termination Analysis Of Active Rules

Active databases extend the functionality of traditional(passive) databases. They generally use Event-Condition-Action (ECA) rule to express their active behaviour. The event part, which specifies a list of events, the condition part,which is a query on the database, and the action part, which generally consists of one or more updates or queries on thedatabase. An important issue in designing a set of rules is to generate rules for which it is possible to guarantee rules can not trigger each other infinitely,i.e., the execution is terminate.Termination reflects desirable behavior property of active database systems.There are several static and dynamic approaches for active rules termination analysis. We consider only static methods that at compile time detect potential non-terminating active rules execution. The static approaches include graph and algebraic approach,and graph includes triggering graph,activation graph,deactivation graph and rule reduction method based on triggering and activation graphs.In this paper,we introduce these approaches respectively and present algorithm and theorem which proved to be correct.In order to overcome limitation of graph termination analysis mothod ,a new method for rule termination analysis within active databases is introduced.This method analyzes how user transaction information and structures can affect active rule execution termination.The algorithm for testing rule termination is presented and proved to be correct. In this paper triggers information and transaction updates are considered in order to study rules termination and simulate execution. We present the algorithm for testing rule termination. The proposed approach turns out to be practical and general with respect to various rules languages and thus it may be applied to many database systems.Finally, we have presented a model for the analysis of termination of a set of active rules: the known results about these properties in the field of deductive databases with their extensions are transferred to the active ECA rules, so that sufficient conditions for the active rules to terminate are provided.Since the...