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. 13, 1998
Filed:
Jun. 30, 1997
Michelle M Jou, San Jose, CA (US);
Ting Yu Leung, San Jose, CA (US);
Mir Hamid Pirahesh, San Jose, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A relational database management system (RDBMS) efficiently evaluates correlated subqueries by decorrelating them and taking care of the so-called SQL count bug and yet avoid using the expensive outer join operation. When there is no tuple match from a correlated subquery, the RDBMS query processor returns a tuple of null(s) from a scalar derived table, and then uses COALESCE function to generate a proper count value of zero from the null. The correlation level remains one. The query processor also performs a pass-through optimization to eliminate a join operation for floating SELECT operation by removing a join operation involving the magic operation, so that the correlation bindings are received from the correlation source table rather than the magic operation.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile