1. A computer that is connected to at least one storage device that stores data of a data base and a data base host that accesses to the data within the data base, the computer comprising: a first interface section that is connected to the data base host; a second interface section that is connected to the at least one storage device; a control unit; and a cache memory, wherein the first interface section receives from the data base host an execution plan for a data base management processing to be executed by the data base host, the control unit preliminarily obtains first identification information indicative of a storage region in the at least one storage device that stores the data to be accessed by the data base host based on the execution plan, the control unit converts the first identification information into second identification information that is used to indicate the storage region on a network that is connected to the computer and the at least one storage device, the second interface section transmits a first read request including the second identification information, which requests to read data stored in the storage region, the second interface section receives data read out from the storage region, and stores the data in the cache memory, and the first interface section transmits the data stored in the cache memory to the data base host when the first interface section receives an access request including the first identification information from the data base host.