Technical Report No. 85, April 1997 - Abstract

Schlepphorst, C.:
Semi-naive Evaluation of F-logic Programs

The semi-naive evaluation strategy is one of the most common optimization techniques for enhancing bottom-up evaluation in the field of deductive databases. It is almost a must for a deductive database system to have this strategy implemented. F-logic is a powerful language combining the advantages of deductive databases with the rich modelling capabilities of object oriented concepts (objects, methods, class hierarchy, non-monotonic inheritance, signatures). As the syntax and semantics of F-logic are much more powerful than that of Datalog, no suitable notion of unification exists so that the strategy of semi-naive evaluation is not applicable in a straightforward way. This paper investigates the difficulties arising and presents an algorithm for an incremental bottom-up evaluation of F-logic programs which has been implemented by the FLORID prototype.