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    METHOD AND DEVICE FOR EXECUTING CONNECTION QUESTION IN DATA BASE SYSTEM
    1.
    发明专利
    METHOD AND DEVICE FOR EXECUTING CONNECTION QUESTION IN DATA BASE SYSTEM 失效

    公开(公告)号：JPH10320423A

    公开(公告)日：1998-12-04

    申请号：JP9482898

    申请日：1998-04-07

    Applicant: INFORMIX SOFTWARE INC

    Inventor： KRISHNA MURALI M ,  KASHYAP ANURAG ,  GERBER ROBERT HOWARD ,  TAYLOR PAUL SHERWOOD ,  SHURTS SCOTT ALAN ,  NI SHENGSONG ,  SUNDARESAN PRAKASH

    IPC: G06F12/00 ,  G06F17/30

    Abstract: PROBLEM TO BE SOLVED: To generate a response to a connection by using a map for erasing a segment which can not satisfy a connected predicate. SOLUTION: A connection has a connected predicate between a 1st table having plural 1st fragments and a 2nd table having plural 2nd fragments and concerning the respective correspondent fragments from the 1st table, a retrieved connection fragment identifies a fragment from the 2nd table including a record satisfying the connected predicate with a record from a correspondent fragment from the 1st table. In order to delete the other fragments, a data base system generates or accesses a connection fragment map 36 in a data base 30. The connection fragment map 36 does not include any record indicating which fragment from two tables can satisfy the connected predicate but shows the unnecessity of retrieval during the execution of question and is used for deleting fragments which can not satisfy the connected predicate.

    CONNECTION ORDERING METHOD UTILIZING DENSITY
    2.
    发明专利
    CONNECTION ORDERING METHOD UTILIZING DENSITY 失效

    公开(公告)号：JPH117454A

    公开(公告)日：1999-01-12

    申请号：JP11925298

    申请日：1998-04-28

    Applicant: INFORMIX SOFTWARE INC

    Inventor： KRISHNA MURALI M

    IPC: G06F17/30 ,  G06F17/00

    Abstract: PROBLEM TO BE SOLVED: To provide an efficient and correct method for estimating an optimum connection order. SOLUTION: The method optimizes connection inquiry processing based on connection density. In embodiment, a method for an inquiry optimizing device in a relational data base management system is implemented. The good connection order of multiple connection inquiries is found out by a metric system for mutually comparing the relative merits of candidate connection order as a whole. In the embodiment, the connection selectivity of an external key/ external key connection is estimated so that both of participating tables are external keys of a basic or inherent key in a basic table. Inquiry graph expression is processed to estimate extremely many optional filters including all combinations of basic key/external key connection and external key/external key connection and the connection density of connection.

    CARDINALITY-BASED JOIN ORDERING
    9.
    发明专利
    CARDINALITY-BASED JOIN ORDERING 未知

    公开(公告)号：CA2236494A1

    公开(公告)日：1998-11-02

    申请号：CA2236494

    申请日：1998-05-01

    Applicant: INFORMIX SOFTWARE INC

    Inventor： KRISHNA MURALI M

    IPC: G06F17/30 ,  G06F17/00

    Abstract: Method and apparatus for optimizing the processing of join queries based on join cardinality. Embodiments implement the methods in query optimizers in relational database management systems. A good join order for a multiple join query is found with a metric that compares the relative merits of candidate join orders as a whole. Embodiments estimate the join selectivity of foreign key - foreign key joins, where both participating tables are foreign keys with respect to a primary or unique key of one primary table. A graph representation of a query is processed to estimate the join cardinality of an arbitrarily large number of filters and joins, including any combination of primary key - foreign key joins and foreign key - foreign key joins.

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