ACTIVE INTERDATABASE DEPENDENCIES

This paper describes an active semantic database model that copes with the issues of automatic enforcement of dependencies among various por tions of fragmented (possibly heterogenous) database. Dependencies are defined as computational invariants, which are database schema primit ives. The invariants are defined independently of implementation issue s such as distribution of the database and physical tool of implementa tion. Dependency definitions are translated into PATH structures (impl ementation-independent knowledge representation entities) that accumul ate syntactic and semantic knowledge about the dependencies. After com pletion of the physical design, the PATH structures are refined using DMP (distributed matching protocol), which determines the contents of interdatabase transactions to maintain the consistency of a distribute d system relative to the defined-sequence of invariants. The paper dis cusses these concepts and relevant implementation issues and illustrat es the concepts using a complete case study.