In today's highly interconnected networks there is an increasing need to communicate among databases located at different sites and built using different data models. The interoperability problem is made more difficult by the fact that in many data models there is often an unclear relationship between the actual representations and the abstract meanings of the databases. Hence it is unwieldy to interoperate directly among pairs of those models. However, a clear relationship exists between representation and meaning in constraint databases, which are actually a set of data models parameterized by the types of constraints allowed in the language. This project demonstrates how to express most of the practical temporal and spatial data models using constraint databases and how to solve in this context the interoperability problem. Translations between different data models are expressed as queries in constraint query languages. In addition, constraint query languages serve as a convenient intermediate layer for query translation between different query languages. This project explores the theoretical foundations of constraint-based database interoperability and its practical applications. It will facilitate data sharing and query reuse among different temporal and spatial database applications.
