Setting up Transaction and Roll-back Logging

DP4 maintains a roll-back log and a transaction log to help ensure the security and integrity of the database. The roll-back log stores images of data before changes are made and the transaction log records each database transaction.

Transaction logging is turned on when you first install DP4 to ensure that roll-forward recovery can be used. The transaction log has the same name as your database, and the extension .LOG.

Roll-back logging is also switched on as standard to make it possible to restart without restoring from a backup copy of the database in the event of a system failure. The roll-back log has the same name as your database, and the extension .RLB. The log is deleted when you exit DP4.

To set up roll-back and transaction logging:

1. On the DP4 System Main menu, select the Configuration Options:

   

   The System and User Setup Options menu is displayed

   

2. Select option 1 - System configuration which will cause the DP4 System Setup menu to be displayed:

   

3. On the System Setup menu, select option 2 - Console/Transaction logging and the Console/Transaction Logging screen is then displayed:

   

   Only the first seven options are relevant to logging; click on them in the illustration above for further information. The very last option is also important for database maintenance. It is a good idea to ensure that regular integrity checks are performed on your DP4 databases.

4. Complete the entry screen, pressing <Tab> to save your changes. A message is displayed prompting you to re-boot your machine for the changes to take effect. Press a key to remove the message, and <Esc> to return to the DP4 System menu.

5. The database manager is not aware of the changes until it is shut down and re-started. Re-boot the machine if the database manager is loaded to remain in memory. Windows users re-start Windows, or shutdown and restart DP4.

Auditing the Transaction Log describes how you can view the contents of the transaction log.