A framework for merging, repairing and querying inconsistent databases

This paper presents a framework for merging, repairing and querying inconsistent databases in the presence of functional dependencies and foreign key constraints and investigates the problem related to the satisfaction of general integrity constraints in the presence of null values. In more details, the approach consists in i) merging the source databases to reduce the set of tuples inconsistent with respect to the constraints defined by the primary keys, ii) repairing the integrated database with respect to functional dependencies and foreign key constraints, and iii) computing consistent answers over repaired database. This paper presents a system prototype, RAINBOW, developed at the University of Calabria, implementing the proposed framework. The system receives in input an integration operator and a query and outputs the answer to the query. The system currently implements many of the integration operators proposed in the literature.