| 摘要 |
There are provided a backup version page table in a storage for providing a correspondence between the pages of a database and the slots in a database storage medium in which the contents of pages to be recovered, if necessary, are stored; a current version page table for providing a correspondence between pages updated by a transaction and slots in the database storage medium wherein the updated contents of the pages are stored; and a journal file for recording various system journals; wherein the updated page contents are stored in the database stored medium at the slots not-used at that time and found with reference to the backup version page table and the current version page table. According to an aspect of another embodiment, there are provided a database constructed of a plurality of sub-areas; a differential file for each sub-area, and a backup file for each sub-area for copying the contents of each sub-area; wherein if the information in a certain sub-area of said database is updated, the updated information is stored in the differential file for the sub-area, and information is recovered using the backup file and the differential file for the certain sub-area. |
