Abstract not found

Managing inter schema knowledge is an essential task when dealing with cooperative information systems. We propose a logical approach to the problem of both expressing inter schema knowledge, and reasoning about it. In particular, we set up a logical language for expressing semantic interdependencies between classes belonging to different database schemas, and show that reasoning overs uch interdependencies is decidable. This yields the possibility of building a logic-based module that can draw useful inferences whenever the need arises of both checking coherence between the knowledge represented in different schemas, and combining the results of a set of queries referring to different databases.