Datalog++: A Basis for Active Object-Oriented Databases

We consider in this paper an extension of Datalog with mechanisms for temporal, non monotonic and non deterministic reasoning, which we refer to as Datalog++. First, we study its semantics, and show how iterated fixpoint and stable model semantics can be combined to the purpose of clarifying the interpretation of Datalog++ programs, and supporting their efficient execution. Second, we exhibit a compilation into Datalog++ of an active/deductive object-oriented model, ADOOD, including the schema definition language, the query language with multiple roles, the basic update operations, and a form of active rules. The proposed compilation is intended both to illustrate the expressiveness of Datalog++, and to provide a more flexible programming front-end to it. Finally, we illustrate the use of ADOOD by means of examples from semistructured data management.