Towards Efficient Evaluation of Methods by Reduction

Bottom-up evaluation of DOOD programs is improved by adding functional reduction as call--by--need computation for scalar methods. To that aim methods, conceived as a functional language, have to satisfy certain properties, like uniqueness and directed use from call to result. In this paper we propose declarative and operational semantics of such methods, formalize the required properties, and show the integration of reduction and bottom-up evaluation. In an experiment this approach shows a better performance than a top-down technique and magic set optimization. 1 Introduction During the last decade much research has been done to develop logics for object--oriented databases. Typically such approaches comprise object--identity, methods, classes, and inheritance. Moreover, in advanced languages like F-logic [4, 8], schema and data are handled at a uniform level, enabling among others, the data--dependent definition of classes. If such a logic is used as a deductive rule language, due t..