Prioritized Repairing and Consistent Query Answering in Relational Databases

TL;DR

This paper explores a framework for preferred consistent query answering in relational databases, incorporating user preferences to prioritize repairs and analyzing the properties and computational complexity of these methods.

Contribution

It introduces a formal framework for preferred repairs in inconsistent databases, including axioms, three repair families, and complexity analysis.

Findings

Three families of preferred repairs are defined and related.

Preferred repairs can significantly reduce the repair space.

Computational complexity varies across different preferred repair strategies.

Abstract

A consistent query answer in an inconsistent database is an answer obtained in every (minimal) repair. The repairs are obtained by resolving all conflicts in all possible ways. Often, however, the user is able to provide a preference on how conflicts should be resolved. We investigate here the framework of preferred consistent query answers, in which user preferences are used to narrow down the set of repairs to a set of preferred repairs. We axiomatize desirable properties of preferred repairs. We present three different families of preferred repairs and study their mutual relationships. Finally, we investigate the complexity of preferred repairing and computing preferred consistent query answers.