The LLUNATIC data-cleaning framework

Data-cleaning (or data-repairing) is considered a crucial problem in many database-related tasks. It consists in making a database con-sistent with respect to a set of given constraints. In recent years, repairing methods have been proposed for several classes of con-straints. However, these methods rely on ad hoc decisions and tend to hard-code the strategy to repair conflicting values. As a conse-quence, there is currently no general algorithm to solve database repairing problems that involve different kinds of constraints and different strategies to select preferred values. In this paper we de-velop a uniform framework to solve this problem. We propose a new semantics for repairs, and a chase-based algorithm to compute minimal solutions. We implemented the framework in a DBMS-based prototype, and we report experimental results that confirm its good scalability and superior quality in computing repairs. 1