发明授权
US08041726B2 System for executing a query having multiple distinct key columns
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用于执行具有多个不同键列的查询的系统
- 专利标题： System for executing a query having multiple distinct key columns
- 专利标题（中）： 用于执行具有多个不同键列的查询的系统
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申请号： US12212431申请日： 2008-09-17
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公开(公告)号： US08041726B2公开(公告)日： 2011-10-18
- 发明人: Yao-Ching Chen , You-Chin Fuh , Allan B. Lebovitz , Li-Mey Lee , Fen-Ling Lin , Lee-Chin Hsu Liu , Yun Wang , Binghua Zhen
- 申请人： Yao-Ching Chen , You-Chin Fuh , Allan B. Lebovitz , Li-Mey Lee , Fen-Ling Lin , Lee-Chin Hsu Liu , Yun Wang , Binghua Zhen
- 申请人地址： US NY Armonk
- 专利权人： International Business Machines Corporation
- 当前专利权人： International Business Machines Corporation
- 当前专利权人地址： US NY Armonk
- 代理机构： Sawyer Law Group, P.C.
- 主分类号： G06F17/30
- IPC分类号： G06F17/30 ; G06F7/00
摘要：
A system and computer readable medium for executing a query to access data stored in a database, wherein the query includes a plurality of DISTINCT keys, is disclosed. The system and computer readable medium includes a capture module for identifying each of the plurality of DISTINCT keys in the query and a sort module coupled to the capture module for determining if more than one sort is needed to execute the query, performing a first DISTINCT operation on a first DISTINCT key of the plurality of DISTINCT keys, storing data fetched from the first DISTINCT operation in a master workfile only if more than one sort process is needed to execute the query, and utilizing the master workfile to perform subsequent DISTINCT operations on the other of the plurality of DISTINCT keys.