Implementing Abstract Objects with Inheritance in Datalog~(neg)

摘要

We present an elegant technique to reduce inheritance and encapsulation to pure deduction. The reduction technique presented in this paper makes it possible to model object-oriented database features in a purely deductive system. Encapsulation has been given a formal treatment for the first time by introducing the so called context-resolution scheme. The completion technique presented in this paper elegantly tackles inheritance with overriding and conflict resolution by avoiding non-monotonic reasoning. We show that the completion based reduction technique is robust and appealing compared to any other known rewriting based approaches. We propose an object-oriented front-end language called the Datalog++, and discuss a rewriting scheme to the acclaimed Datalog~(neg) for this language that exploits the context resolution and completion techniques presented here. We claim that our approach outperforms other known approaches in the literature in terms of its modeling capabilities and efficiency. Unlike most others, an implementation based on our reduction technique does not require meta-interpretation and consequently readily exploits the rich set of optimization techniques available in Datalog~(neg).