The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 27, 1999
Filed:
Jul. 16, 1997
Shaul Dar, Tel Aviv, IL;
Hosagrahar Visvesvaraya Jagadish, Berkeley Heights, NJ (US);
Alon Yitzchak Levy, Seattle, WA (US);
Divesh Srivastava, Summit, NJ (US);
AT&T Corp, Middletown, NJ (US);
Abstract
The present invention is a method and system for using materialized views to compute answers to SQL queries with grouping and aggregation. A query is evaluated a using a materialized view. The materialized view is semantically analyzed to determine whether the materialized view is usable in evaluating an input query. The semantic analysis includes determining that the materialized view does not project out any columns needed to evaluate the input query and determining that the view does not discard any tuple that satisfies a condition enforced in the input query. If the view is usable, the input query is rewritten to produce an output query that is multi-set equivalent to the input query and that specifies one or more occurrences of the materialized view as a source of information to be returned by the output query. The output query is then evaluated. The semantic analysis and rewriting may be iterated, with the output query of each iteration being the input query of the next iteration. The output query is evaluated after the last iteration.