Title :
Preferred repairs for inconsistent databases
Author :
Greco, S. ; Sirangelo, C. ; Trubitsyna, I. ; Zumpano, E.
Author_Institution :
DEIS, Univ. della Calabria, Italy
Abstract :
The objective of this paper is to investigate the problems related to the extensional integration of information sources. In particular, we propose an approach for managing inconsistent databases, i.e. databases violating integrity constraints. The presence of inconsistent data can be resolved by "repairing" the database, i.e. by providing a computational mechanism that ensures obtaining consistent "scenarios" of the information or by consistently answering to queries posed on an inconsistent set of data. In this paper we consider preferences among repairs and possible answers by introducing a partial order among them on the base of some preference criteria. More specifically, preferences are expressed by considering polynomial functions applied to repairs and returning real numbers. The goodness of a repair is measured by estimating how much it violates the desiderata conditions and a repair is preferred if it minimizes the value of the polynomial function used to express the preference criteria. The main contribution of this work consists in the proposal of a logic approach for querying and repairing inconsistent databases that extends previous works by allowing to express and manage preference criteria. The approach here proposed allows to express reliability on the information sources and is also suitable for expressing decision and optimization problems. The introduction of preference criteria strongly reduces the number of feasible repairs and answers; for special classes of constraints and functions it gives a unique repair and answer.
Keywords :
data integrity; database management systems; information resources; optimisation; query processing; computational mechanism; consistent information scenario; database integrity; desiderata condition; inconsistent database management; inconsistent database repair; information source extensional integration; information source reliability; integrity constraint violation; logic approach; optimization problem; polynomial function minimization; preference criteria; query answering; Data engineering; Databases; Logic; Polynomials; Proposals;
Conference_Titel :
Database Engineering and Applications Symposium, 2003. Proceedings. Seventh International
Print_ISBN :
0-7695-1981-4
DOI :
10.1109/IDEAS.2003.1214927