公开(公告)号：JPH09171478A

公开(公告)日：1997-06-30

申请号：JP18265696

申请日：1996-06-07

Applicant: TANDEM COMPUTERS INC

Inventor： HARII EI RESURII ,  DEBITSUDO DABURIYU BAAZUOORU ,  ROHITO ENU JIEIN ,  HEDEII YAGUMAI

IPC: G06F12/00 ,  G06F17/30

Abstract: PROBLEM TO BE SOLVED: To easily and efficiently search a data base. SOLUTION: Each search key is constructed with a general expression sentence generated by the compiler 128 of the data base management system on the basis of a search question. Each key column indicates another dimension and a range and an IN list are specified with a search question and usable as a multicolum predicate value. A predicate which is not specified with the question is interpreted to specify the maximum value and minimum value of the relative column key. The compiler 128 generates a general expression used by the executor 124 of the system so as to generate a search key. The compiler 128 evaluates the search question by relating the predicate with a cluster and an OR item number assigned to each OR item of the question expression. The executor 124 uses the general expression from the compiler 128, and removes the contradiction between identical column predicates and the redundancy of the predicate value and OR item to decrease and minimize the number of records to be accessed. The search keys are generated in the same order with the indexes that the searches belong to.