Update operations in deductive databases with functional dependencies

Abstract

We study the problem of updating intensional relations in the framework of deductive databases on which integrity constraints (specifically functional dependencies) are defined. First, a formalization of a model-theoretic semantics of updates is provided: the notions ofrepresentability, consistency anddeterminism are introduced to characterize the various cases. Then, a proof-theoretic approach, based on a variant of resolution integrated with the chase procedure, is defined, showing that the method exactly captures the above notions. It turns out that using functional dependencies it is possible to resolve potential ambiguities in several practical cases. Also, precomputations can be performed at definition time to execute update requests more efficiently.