Patent ID: 7711720

Claim:
An application server that retrieves data from a database management system using a retrieval condition received from a terminal and transmits the data retrieved as a retrieval result to the terminal, comprising: a cache memory that stores in a correlated form the retrieval condition and the retrieval result; an update condition setting unit that sets a cache update condition that indicates when the cache memory is to be updated; an update processing unit that determines whether to transmit an update request to update the retrieval result based on the cache update condition; and a main controlling unit that sends, to the database management system, a retrieval expression which is produced based on the retrieval condition received from a client terminal or read from the cache memory, based on the update request received from the update processing unit, and receives the retrieval result of a database from the database management system and stores the retrieval condition and the retrieval result in the correlated form in the cache memory, wherein the update condition setting unit acquires a number of data records updated within a predetermined period from the database, and determines whether the number of data records updated is in a fixed range of the data records and, if the number of data records updated is not in the fixed range, the update condition setting unit sets the cache update condition such that the number of data records updated falls in the fixed range.