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1.发明专利
公开(公告)号：CA2146171A1
公开(公告)日：1996-10-04
申请号：CA2146171
申请日：1995-04-03
Applicant: IBM CANADA
Inventor： SCHIEFER BERNHARD , STRAIN LORI G , YAN WEIPENG P
IPC: G06F16/245 , G06F16/2453 , G06F17/30
Abstract: The present invention provides a method for estimating cardinalities for query processing in a relational database management system. The present method is suitable for use with a query optimizer for estimating cardinalities for sets of columns or keys resulting from a grouping operation or a duplicate removal operation.
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