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Issue No.02 - April (1995 vol.7)
pp: 261-273
ABSTRACT
<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>
INDEX TERMS
deductive database, logic programming, query analysis, query optimization, query processing, recursive query evaluation
CITATION
Jiawei Han, "Chain-Split Evaluation in Deductive Databases", IEEE Transactions on Knowledge & Data Engineering, vol.7, no. 2, pp. 261-273, April 1995, doi:10.1109/69.382296
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