Data of a plurality of master tables can be replicated in one replica table. A job to access a plurality of tables can be executed by accessing one replica table, and hence the job execution time is minimized. A correspondence is established between data using, as a key, particular data in the data of a plurality of master tables. The data field for the key is defined by the replication definition. Timing of replication for the replica table is also defined in the program to execute replication. The replication program generates, at execution thereof, the control table according to the definition and manages the operation states of a plurality of master tables and the replication state of the replica table to thereby conduct replication for the replica table at the defined timing.