| 摘要 |
<P>PROBLEM TO BE SOLVED: To store update contents of updated data each time data is updated, and also efficiently eliminate repetition of stored update contents. <P>SOLUTION: Each time data is updated in a database management device 2, a log input unit 7 inputs an update log entry (record update) 3r indicating update contents of updated data and the next update time at which the data is to be updated next time, and stores the update log entry (record update) 3r in a storage unit 6. Also, the log input unit 7 sets the new current time when a predetermined unit time has passed after the last current time was set. Each time the new current time is set, a log reduction unit 8 deletes the update log entry (record update) 3r indicating the next update time which is before the newly set current time from the storage unit 6. <P>COPYRIGHT: (C)2013,JPO&INPIT |
