Well-behaving rule systems for entity-relationship and object oriented models

Abstract

Integrity Maintenance is considered one of the major application fields of rule triggering systems (RTSs). In the case of a given integrity constraint being violated by a database transaction these systems trigger repairing actions. However, it has been shown that for any set of constraints there exist unrepairable transactions, which depend on the closure of the constraint set. Even if unrepairable transactions are excluded, this does not restrain the RTS from producing undesired behaviour. Analyzing the behaviour of RTSs leads to the definition of critical paths in associated rule hypergraphs and the requirement of such paths being absent. It is shown that this requirement can be satisfied if the underlying set of constraints is stratified and that this is always the case for the structural constraints in Entity-Relationship and object oriented models. Moreover, in both cases there is no ambiguity for the selection of rules.