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. 27, 2013
Filed:
Jul. 18, 2012
Rafi Ahmed, Fremont, CA (US);
Rafi Ahmed, Fremont, CA (US);
Oracle International Corporation, Redwood Shores, CA (US);
Abstract
A method, apparatus, and stored instructions are provided for transforming an initial query having a scalar subquery with correlated predicates into a transformed query having transformed predicates that are not in the scalar subquery. The transformed predicates correspond to the correlated predicates, but the transformed predicates are no longer correlated. The transformed predicates reference an outer join operation to preserve null values that may have been generated by the correlated predicates that were in the scalar subquery of the initial query. The transformed query is semantically equivalent to the initial query. When creating an execution plan for the transformed query, the query processor may choose from a much larger set of access paths, join methods, and join permutations than those that were available for the initial query. The transformed query may qualify for other transformations or optimizations, or may otherwise be executed or optimized differently from the initial query.