Invention Grant
- Patent Title: Transforming a single-table join predicate into a pseudo-join predicate
- Patent Title (中): 将单表连接谓词转换为伪连接谓词
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Application No.: US13481722Application Date: 2012-05-25
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Publication No.: US08554761B1Publication Date: 2013-10-08
- Inventor: Rafi Ahmed
- Applicant: Rafi Ahmed
- Applicant Address: US CA Redwood Shores
- Assignee: Oracle International Corporation
- Current Assignee: Oracle International Corporation
- Current Assignee Address: US CA Redwood Shores
- Agency: Hickman Palermo Truong Becker Bingham Wong LLP
- Main IPC: G06F17/30
- IPC: G06F17/30 ; G06F7/00

Abstract:
Methods, computing devices, and computer-readable media are provided for transforming an initial query with a single-table outer join predicate to a second, semantically equivalent query that includes a multi-table predicate instead of the single-table outer join predicate. Because the second query does not include the single-table outer join predicate, the second query may be available for further transformations or optimization techniques, may produce a more efficient or otherwise different execution plan, or may be executed more efficiently or differently. The single-table outer join predicate may be in a full outer join ON clause of the initial query or nested in a left outer-joined LATERAL VIEW of the initial query. The multi-table predicate may be in a WHERE clause of the second query. Unlike the initial query, the second query allows use of a temporary organization of data from multiple tables for evaluation of multiple rows of the left outer join.
Information query