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:
Feb. 16, 1999
Filed:
Jun. 30, 1997
Roberta Jo Cochrane, Los Gatos, CA (US);
George Lapis, San Jose, CA (US);
Mir Hamid Pirahesh, San Jose, CA (US);
Richard Sefton Sidle, Toronto, CA;
David Everett Simmen, San Jose, CA (US);
Tuong Chanh Truong, San Jose, CA (US);
Monica Sachiye Urata, Saratoga, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
An automated system for detecting and preventing mutating table violations of database integrity in a SQL query before generation and selection of an optimal query execution plan (QEP). This system modifies the query graph model (QGM) to restrict the choice of execution plans to those that avoid mutating table integrity (MTI) violations, thereby forcing database integrity during table mutation when executing the optimal QEP. Mutating table integrity violations are detected by evaluating the position in the QGM of each write-node referencing a particular base table with respect to each of the positions of all other read- and write-nodes referencing of the same base table. Every common-referencing node pair is tested for sequencing conflicts and a data-flow dam is inserted in the QGM where necessary or a poke query is inserted between the nodes to force the completion of the execution of one node before initiating execution of the other common-referencing node. The system of this invention allows processing of all non-cyclic and most cyclic SQL queries known to cause mutating table integrity violations, such as queries having searched and positioned inserts, deletes and updates, and row-level triggers.