The Community for Technology Leaders
Green Image
Issue No. 02 - April (1995 vol. 7)
ISSN: 1041-4347
pp: 261-273
<p><it>Abstract</it>—Many popularly studied recursions in deductive databases can be compiled into one or a set of highly regular chain generating paths, each of which consists of one or a set of connected predicates. Previous studies on chain-based query evaluation in deductive databases take a chain generating path as an inseparable unit in the evaluation. However, some recursions, especially many functional recursions whose compiled chain consists of infinitely evaluable function(s), should be evaluated by chain-split evaluation, which splits a chain generating path into two portions in the evaluation: an immediately evaluable portion and a delayed-evaluation portion. In this paper, the necessity of chain-split evaluation is examined from the points of view of both efficiency and finite evaluation, and three chain-split evaluation techniques: magic sets, buffered evaluation, and partial evaluation are developed. Our study shows that chain-split evaluation is a primitive recursive query evaluation technique for different kinds of recursions, and it can be implemented efficiently in deductive databases by extensions to the existing recursive query evaluation methods.</p>
deductive database, logic programming, query analysis, query optimization, query processing, recursive query evaluation

J. Han, "Chain-Split Evaluation in Deductive Databases," in IEEE Transactions on Knowledge & Data Engineering, vol. 7, no. , pp. 261-273, 1995.
93 ms
(Ver 3.3 (11022016))