"On the Implementation of a Simple Class of Logic Queries for Databases," D. Sacca and C. Zaniolo, Proc. 5th ACM SIGMOD-SIGACT Symposium on Principles of Database Systems, 1986.  Home/Search   Document Not in Database   Summary   Related Articles

....are then passed to anc, to generate yet another subgoal. Several strategies have been proposed for evaluating recursive queries expressed using sets of Horn Clauses (rules) Henschen and Naqvi 84] Kifer and Lozinskii 85] Lozinskii 85] McKay and Shapiro 81] Rohmer and Lescoeur 85] Sacca and Zaniolo 86a] Van Gelder 86] Vieille 86] etc. See [Bancilhon and Ramakrishnan 86] for a comprehensive survey. The main thrust of the above strategies is to improve efficiency by restricting the computation to tuples that are related to the query. They all use information passing in some form, but they ....

....in the invocation of a predicate. This is done using indices that essentially encode the structure of the computation used to generate a fact. These indices allow us to perform certain powerful optimizations in some cases. The Counting method was in fact originally presented [Bancilhon et al. 86, Sacca and Zaniolo 86a] with these optimizations as an integral part of the transformation. Like the Magic Sets method, the original version was of restricted applicability, and for example, could not handle the same generation example that we have used as a running example. We have chosen to separate the indexing ....

"On the Implementation of a Simple Class of Logic Queries for Databases," D. Sacca and C. Zaniolo, Proc. 5th ACM SIGMOD-SIGACT Symposium on Principles of Database Systems, 1986.

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