In a system that switches multiple database servers to separate computers, a switching order of the database servers is variably changed and set. In the system that allows an executive system computer and a standby system computer having the database servers to share a database respectively, the system is switched from the database server of the executive system computer to the database server of the standby system computer. Information (order information) that indicates an order in which the system of the executive system database server is switched is registered in a storage device. The order information is changed by detection of the occurrence of an event in the executive system computer. The system switching processing is performed from the executive system database server to the standby system database server in accordance with the changed order information.