Discovering view expressions from a multi-source information system

A Multi-Source Information System is composed of a set of independent data sources and a set of views defined as queries over these data sources. This problem is dramatically increased in evolving information systems, such as data warehouses and Web systems, where several views are daily defined or modified by users who are not aware of the detailed metadata describing data sources and their interrelationships. The purpose of the paper is to propose a design aid which helps in the definition of a user view (or query) from its schema and some integrity constraints. Our approach defines a solution space which provides the set of potential queries that correspond to the user view. The approach is based on the existence of metadata describing individual sources, on semantic assertions describing inter-source similarities between concepts, and on some heuristics which reduce the size of the solution space