A Unified Semantics for Active and Deductive Databases

These two rule-oriented paradigms of databases have been the focus of extensive research and are now coming of age in the commercial DBMS world. However, the systems developed so far support well only one of the two paradigms|thus limiting the eeectiveness of such systems in many applications that require complete integration of both kinds of rules. In this paper, we discuss the technical problems that make such an integration diicult, and trace their roots to a lack of a uniied underlying semantics. Then, we review recent advances in the semantics of non-monotonic logic and show that they can be used to unify the foundations of active databases and deductive databases. Finally, we outline the design a new rule language for databases that integrates a deductive system with a trigger-based DBMS.