On Active Deductive Databases: The Statelog Approach
Georg Lausen, Bertram Ludäscher, Wolfgang May
Abstract.
After briefly reviewing the basic notions and terminology of active rules and relating them to production rules and deductive rules, respectively, we survey a number of formal approaches to active rules. Subsequently, we present our own state-oriented logical approach to active rules which combines the declarative semantics of deductive rules with the possibility to define updates in the style of production rules and active rules. The resulting language Statelog is surprisingly simple, yet captures many features of active rules including composite event detection and different coupling modes. Thus, it can be used for the formal analysis of rule properties like termination and expressive power. Finally, we show how nested transactions can be modeled in Statelog, both from the operational and the model-theoretic perspective.