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:
Oct. 01, 2002
Filed:
Sep. 14, 1998
Roberta Jo Cochrane, Los Gatos, CA (US);
George Lapis, San Jose, CA (US);
Ting Yu Leung, San Jose, CA (US);
Mir Hamid Pirahesh, San Jose, CA (US);
Monica Sachiye Urata, Saratoga, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method, apparatus, and article of manufacture for optimizing database queries uses a derived summary table, wherein a definition of the summary table is based on a full select statement that is materialized in the table and describes how the summary table was derived. The summary table definition can be a complex query involving nested GROUP BY operations as well as complex HAVING clauses with subqueries or join operations. A query is analyzed using subsumption tests between the query and the definition of the summary table to determine whether expressions occurring anywhere in the query, but not in the summary table, can be subsumed in the summary table. In performing the query, an expression in the query is subsumed in the summary table when the expression can be re-derived from one or more of the columns of the summary table.