System for executing a query having multiple distinct key columns

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 quer...

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Bibliographic Details
Main Authors Chen, Yao-Ching, Fuh, You-Chin, Lebovitz, Allan B, Lee, Li-Mey, Lin, Fen-Ling, Liu, Lee-Chin Hsu, Wang, Yun, Zhen, Binghua
Format Patent
LanguageEnglish
Published 18.10.2011
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Summary: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.