Patent ID: 6694306
Filing Date: 2004-02-17
Classification: G06F,Y10S

Abstract:
A query processing system connected, through a network, with at least one client to run application programs and with a plurality of servers each having at least one database, which receives a query from said client and returns the result of the query;said query processing system having: at least one virtual table composed of a plurality of virtual columns which contain no real data and are mapped to columns of real databases, wherein, individual names of the virtual columns are provided to said application programs and multiple mappings to different columns of different databases can be defined on each of the virtual columns; a virtual table manager which manages said virtual table and provides each of virtual columns, on which multiple mappings are defined, with a switching designation to select one of defined mappings; a query analyzer which analyzes said received query; a query generator which generates a database reference query from the query analyzed by said query analyzer to reference said database using the definition of said virtual tables; and a query executor which executes processing of said database reference query generated by said query generator.