Distribution of Selections: The Missing Link between Strategies for Relational Databases and Deductive Databases.
Nobuyoshi Miyazaki · 1989
This paper discusses the relationship between the distribution of selections (DS) and other methods for query processing in deductive databases. A method that distributes selections for general recursive queries is proposed. It is shown that there is a guarantee that QSQ and the magic set (MS) are at least as effective as DS as far as the selection propagation is concerned. It is also shown that DS precisely corresponds to a weak variation of MS, and that MS is as effective as DS for non-recursive queries. Hence, MS can be regarded as natural generalizations of the selection-first principle in relational databases.