Project-Join-Repair: An Approach to Consistent Query Answering Under Functional Dependencies

Consistent query answering is the term commonly used for the problem of answering queries on databases that violate certain integrity constraints. We address this problem for universal relations that are inconsistent with respect to a set of functional dependencies. In order to obtain more meaningful repairs, we apply a project-join dependency prior to repairing by tuple deletion. A positive result is that the additional project-join can yield tractability of consistent query answering. This article extends [21] by providing theorem proofs. Key words: database repairing, consistent query answering. 1 Motivation In the Internet age, data are ubiquitous and cannot be expected to be globally consistent. The database systems in which such data are stored and queried, should be capable of handling this inconsistency phenomenon. A way to deal with the problem is to rectify the database before proceeding to queries. Since there is usually no single best way to solve an inconsistency, we will...

• Type: Conference
• Year: 2006
• Where: FQAS
• Authors: Jef Wijsen
• Keywords: Consistent Query Answering, Database, FQAS 2006, Possible Database