DISLOG – A Disjunctive Deductive Database Prototype

DISLOG is a system for reasoning in disjunctive deductive databases. It seeks to combine features of disjunctive logic programming, such as the support for incomplete information, with those of deductive databases, such as all–result inference capabilities. Several basic operators are provided for logical and non–monotonic reasoning: The logical consequence operator derives all logically implied disjunctive clauses from a disjunctive database. The non–monotonic operators are semantically founded on generalizations of the well–known closed–world–assumption and the negation–as–failure concept. Reasoning in disjunctive deductive databases is very complex, even for small examples. Many different optimization techniques are integrated in DISLOG to speed up the application performance. The clause tree is used as a data structure that allows for an efficient and transparent evaluation. The DISLOG–system has been developed in PROLOG – currently a core part of D ISLOG is reimplemented in C++. DISLOG offers two different types of user interfaces. The user–friendly interfaces allow for quickly experimenting with semantics on example databases – which can even be done remotely through the WWW. The DISLOG–library provides various operators that can be loaded into PROLOG applications.