REPRESENTING AND USING INTERSCHEMA KNOWLEDGE IN COOPERATIVE INFORMATION SYSTEMS

Managing interschema knowledge is an essential task when dealing with cooperative information systems. We propose a logical approach to the problem of both expressing interschema knowledge, and reasoning about it. In particular, we set up a structured representation language for expressing semantic interdependencies between classes belonging to different database schemas, and present a method for reasoning over such. interdependencies. The language and the associated reasoning technique makes it possible to build a logic-based module that can draw useful inferences whenever the need arises of both comparing and combining the knowledge represented in the various schemas. Notable examples of such inferences include checking the coherence of interschema knowledge, and providing integrated access to a cooperative information system.