A Structural Model of ECA Rules in Active Database

Abstract

Active database systems have been developed for applications needing an automatic reaction in response to certain conditions being satisfied or certain event occurring. The desired behavior is expressed by ECA-rules (event-condition-action rules). Generally, ECA rules and their execution are represented by rule language, for example, defining TRIGGERs in an active database. Then, database behavior prediction or analysis can be realized through other approaches such as algebraic approach, trigger graph methods, etc.. Therefore, in such active databases, rule representation and processing are separated. In this paper we propose a structural model which integrates rule representation and processing entirely, it is called Conditional Colored Petri Net (CCPN). CCPN can model both rules themselves and their complicated interacting relation in an graphical way. If the rule base of an active database is modeled by CCPN, then rule simulation can be done. An example is illustrated in the paper.