Enhancing ECA Rules for Distributed Active Database Systems

Abstract. ECA (event/condition/action) rules have been developed for central active database systems. In distributed active database systems the problem of inaccessibility of partial systems raises and thus the undecidability of ECA con-ditions referring to remote systems. This work proposes an enhancement of ECA rules for distributed active database systems to react also in the case of in-accessibility and undecidability. Therefore, the ECA evaluation will be en-hanced to a strict function with the inaccessibility state Ω and a new alternative action AA enriches the classical ECA rules. The advantages and the usage of this approach are shown by an example of maintaining data consistency in dis-tributed active database systems.