Quality-Driven Query Processing Techniques in the MOMIS Integration System

In the NeP4B project the MOMIS data integration system was extended with data quality concepts. Starting from this obtained framework, the aim of this paper is twofold; first, we consider data quality metadata in the specification of queries on the Global Schema of the integration system; in this way we can express the quality of the retrieved data by means of threshold of acceptance. Second, we will discuss how the quality constraints specified in the query are useful to perform some query optimization techniques