Towards Integrity Constraints in OWL

Abstract

In many data-centric applications, it is desirable to use OWL as an expressive schema language with which one expresses constraints that must be satisfied by instance data. However, specific aspects of OWL's standard semantics|i.e., the Open World Assumption (OWA) and the absence of Unique Name Assumption (UNA)|make it difficult to use OWL in this way. What triggers a constraint violation in closed world systems leads to new inferences in standard OWL systems. In this paper, we show how defining an Integrity Constraint (IC) semantics for OWL axioms can overcome this problem and discuss possible semantics for ICs. We examine IC semantics discussed in the deductive databases literature, discuss how to adopt these approaches for OWL, and compare it with existing proposals for ICs in OWL. We show IC validation problem can be reduced to SPARQL query answering using off-the-shelf reasoner and present our preliminary results with a prototype implementation using Pellet.