公开(公告)号：JPH1125096A

公开(公告)日：1999-01-29

申请号：JP16844596

申请日：1996-06-07

Applicant: TANDEM COMPUTERS INC

Inventor： LESLIE HARRY A ,  BIRDSALL DAVID W ,  JAIN ROHIT N ,  YAGHMAI HEDIEH

IPC: G06F12/00 ,  G06F17/30

Abstract: PROBLEM TO BE SOLVED: To efficiently and easily search a data base by designating the range and IN list of many key columns, and constructing each search key by a user. SOLUTION: A computer system 100 is a distributed computer system which is provided with plural computers 102, 104, and 106 mutually connected through a local area network medium and a wide area network medium 108. The value of a predicate designated by a search question is evaluated. The value of the equivalent range is assigned to a key column corresponding to each value of each predicate designated as the value of one range. Also, the value of the equivalent range is assigned to a key column corresponding to each value of each predicate designated as the value of an IN list. Moreover, the value of a certain range is assigned to a key column corresponding to each value of each non-designated predicate. Thus, each search key can be constructed by using those values to be assigned.

公开(公告)号：CA2178264A1

公开(公告)日：1996-12-08

申请号：CA2178264

申请日：1996-06-05

Applicant: TANDEM COMPUTERS INC

Inventor： LESLIE HARRY A ,  BIRDSALL DAVID W ,  JAIN ROHIT ,  YAGHMAI HEDIEH

IPC: G06F12/00 ,  G06F17/30

Abstract: A database management system (DBMS) provided with a multi-dimensional improved indexed accessing capability using keyed index searching. Individual search keys are constructed from general expression statements created in the DBMS compiler from search queries supplied to the DBMS. Each key column represents another dimension, and both ranges and IN lists can be specified in the search query and used as the predicate values in multiple columns. Missing predicate values in the search query are interpreted as a specification of the minimum and maximum values for the associated search key column. During compile time, the DBMS compiler produces general expressions to be used by the DBMS executor during run time to create the search keys. The DBMS compiler evaluates search queries by associating predicates with clusters and disjunct numbers assigned to each individual disjunct in the search query expression. The DBMS executor uses the general expression from the compiler and eliminates any conflicts among same column predicates, removes redundancies in predicate values and disjuncts and reduces the number of records to be accessed to the minimum required to complete the search query. The individual search keys are generated in the same order as the index to which the search pertains (i.e., increasing or decreasing order).