METHOD FOR COMBINING TABLES OF ASSOCIATED DATABASE CONTROLLING APPARATUS AND COMPUTER SYSTEM THEREFOR

摘要

PURPOSE: To obtain a merging technology which uses existent data base structure by making good use of characteristics of nested loop merging technology and classifying/merging technology. CONSTITUTION: The relational data base management device retrieves the indexes of merging columns of an inside table first and sequences them. The indexes of the merging columns are scanned to rows of the inside table where the indexes of the merging columns of the inside table have merging column values matching rows of an outside table. Then, a tentative work table including the identifiers of the rows of the inside table having merging column values matching with the outside table is generated by connecting row identifiers with the matching rows of the outside table. Then, the tentative work table is sequenced with the identifiers and an identifier list of the inside table is used to retrieve corresponding rows of the table; and all local predicates are added to the inside table and merged with the matching rows of the outside, so that the result is returned to a user.