Rules Termination Analysis Based on Petri Nets: Implementation Issues

Active database systems (ADBSs) support the specification and implementation of reactive behaviour. This functionality is commonly defined in terms of event-condition-action rules (ECA-rules). The meaning of such a rule is "if the event occurs and the condition holds, execute the action". Rules in ADBSs can be very difficult to program, due to the unstructured and unpredictable nature of rule processing. In this paper, we expose briefly a method of termination analysis of rules (in an ADBS) based on Petri nets and give an object-oriented representation to implement it. In this approach, not only composite events can affect the termination of a set of active rules but also the rules priority.