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:
Sep. 25, 2007
Filed:
Apr. 29, 2003
Qi Cheng, North York, CA;
Linqi Liu, Toronto, CA;
Wenbin MA, Toronto, CA;
Mir Hamid Pirahesh, San Jose, CA (US);
Calisto P. Zuzarte, Pickering, CA;
Qi Cheng, North York, CA;
Linqi Liu, Toronto, CA;
Wenbin Ma, Toronto, CA;
Mir Hamid Pirahesh, San Jose, CA (US);
Calisto P. Zuzarte, Pickering, CA;
International Business Machines Corporation, Armonk, NY (US);
Abstract
A system and method transform queries with subqueries, using window aggregation. An optimizer in a relational database management system transforms queries to optimize their efficiency and speed. The method transforms queries that have a subquery, replacing the subquery with a window aggregation function. In the case of a correlated subquery, the window aggregation function is partitioned by a correlated column of a correlated table. All data in the main select clause, or outer block, of the query that was obtained through references to the correlated table is instead obtained through the new window aggregation subquery. By using window aggregation, the aggregation is performed at the same time as the selection of relevant data from the correlated table, thereby compiling all needed data in a single pass through the table or view. Reducing the number of times that tables or views are accessed reduces the computational demands of a query.