Patent ID: 7152067

Claim:
A multi-database system comprising: a plurality of database devices for storing distributed data; a multi-database processing device coupled to the plurality of database devices over a network to receive the distributed data and perform an integration process on the distributed data received from the plurality of database devices, the integration process generating integrally processed data from the distributed data received from the plurality of database devices; and a user processing device coupled to the multi-database system over the network, the user processing device being configured to send a query request to the multi-database processing device and receive integrally processed data from the multi-database processing device, wherein the multi-database processing includes at least one concealment column which stores confidential information; wherein the query request relates to first and second portions of the distributed data and includes first information for converting associated with the first portion of the distributed data to encrypt data, wherein the multi-database processing device transmits a plurality of data requests to the plurality of database devices in response to the query request, the plurality of data request including a first data request including the first information and a second data request not including the first information, wherein the plurality of the database devices includes a first database device that receives the first data request and a second database device that receives the second data request, the first and second database devices retrieving the first and second portions of the distributed data, respectively, according to the first and second data requests, the first database device converting the first portion of the distributed data to the encrypted data based on a given rule of encryption according to the first information, wherein the multi-database processing device receives the first and second portions of the distributed data from the first and second database devices, respectively, to generate the integrally processed data, the first portion having been converted to the encrypted data by the first database device and the second portion not having been converted by the second database device; and wherein the multi-database processing device controls the decomposition and execution of the query requests such that when the users executes the query requests including the concealment columns, the user does not perform an arithmetic using the concealment columns.