Incremental Integrity Checking: Limitations and Possibilities

Integrity checking is an essential means for the preservation of the intended semantics of a deductive database. Incrementality is the only feasible approach to checking and can be obtained with respect to given update patterns by exploiting query optimization techniques. By reducing the problem to query containment, we show that no procedure exists that always returns the best incremental test (aka simplification of integrity constraints), and this according to any reasonable criterion measuring the checking effort. In spite of this theoretical limitation, we develop an effective procedure allowing general parametric updates that, for given database classes, returns ideal simplifications and also applies to recursive databases. Finally, we point out the improvements with respect to previous methods based on an experimental evaluation.