发明授权
US07873629B1 Dynamic partition enhanced inequality joining using a value-count index
有权
动态分区增强使用数值计数索引的不等式加入
- 专利标题: Dynamic partition enhanced inequality joining using a value-count index
- 专利标题(中): 动态分区增强使用数值计数索引的不等式加入
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申请号: US10862649申请日: 2004-06-07
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公开(公告)号: US07873629B1公开(公告)日: 2011-01-18
- 发明人: J. Mark Morris , Bhashyam Ramesh
- 申请人: J. Mark Morris , Bhashyam Ramesh
- 申请人地址: US OH Dayton
- 专利权人: Teradata US, Inc.
- 当前专利权人: Teradata US, Inc.
- 当前专利权人地址: US OH Dayton
- 代理商 Howard Speight
- 主分类号: G06F7/00
- IPC分类号: G06F7/00 ; G06F17/30
摘要:
Methods, computer programs, and database systems for performing a database query to join a column A and a column B on an inequality condition are disclosed. A database includes value-count indexes for columns A and B. Minimum and a maximum values for A and B are determined, using the value-count indexes for A and B, respectively. The method includes defining three or more sets of values in A and B, relative to the minimum and maximum values for B and A, respectively. The method includes generating one or more Cartesian products between values in A and B. The database query is performed on a set of values in A and a set of values in B to generate a partial query result. The method includes merging one or more Cartesian products and the partial query result.
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