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:
Aug. 06, 1996
Filed:
Jun. 14, 1993
Surajit Chaudhuri, Stanford, CA (US);
Kyuseok Shim, Greenbelt, MD (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
Database applications typically need to invoke foreign functions or to access data that is not stored in the database. The invention provides a comprehensive approach to cost-based optimization of relational queries in the presence of such foreign functions. The optimization takes into account semantic information about foreign functions using a declarative rule language (e.g., SQL) to express such semantics. Procedures for applying the rewrite rules and for generating the execution space of equivalent queries are described. Procedures to obtain an optimal plan from this enriched execution space are also described. Moreover, necessary extensions to the cost model that are needed in the presence of foreign functions are described.