Patent ID: 8874509

Claim:
A client apparatus comprising: a communication unit communicating with a database server apparatus over a network; a first storage unit storing part of a record set included in a database of the database server apparatus; a second storage unit storing a copy of the record set stored in the first storage unit, said copy of the record set disappears from said second storage unit upon losing a power supply; a management unit copying the record set from the first storage unit to the second storage unit upon resumption of said power supply to said second storage unit; and a searching unit searching the second storage unit in response to a search request for data from a user, wherein in response to absence of the requested data in the second storage unit, the searching unit requests the data from the database server apparatus via the communication unit and stores a record containing the requested data returned from the database server apparatus in the second storage unit, and the management unit updates the record set stored in the first storage unit by using update data generated by reference to an order list of the record set stored in the first storage unit and the number of searches recorded, and received from the database server apparatus via the communication unit, and deletes a record, from the second storage unit, for which few search requests have been made.