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Use

When you restore a database, you restore it to the last consistent state it was in before the system failure occurred. To do this, you need uninterrupted data backups and log backups.

You can also restore a database to a state it was in at an earlier point in time in the past.

Table 1: Recovery Types

Recovery Type

Description

Additional Prerequisites

Recover last backup

You restore the last backup from the backup history

The log files dbm.knl and dbm.mdf are not damaged. This means that the backup history is complete.

If you are using third-party backup tools, then the dbm.ebf log file must also be not damaged.

More information: Database Administration, Log Files

Recover specified backup from history

You restore a specific backup from the backup history

The log files dbm.knl and dbm.mdf are not damaged. This means that the backup history is complete.

If you are using third-party backup tools, then the dbm.ebf log file must also be not damaged.

Recover a medium

You restore the backup from a data carrier without referring to the backup history

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Initialize database before recovery

You initialize the database before restoring it

Usually the database system attempts to import redo log entries still present in the log area during recovery. To prevent this and force the deletion of all redo log entries in the log area, initialize the log area before the recovery.

Example

After a training course, you want to restore the training course to its original state by importing a data backup with the original database state. By deleting the redo log entries, you ensure that all changes to the course database made by course participants are discarded.

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Recover until a specific time

You restore the database to its state at a particular point in the past

If the desired point in time is after the last data backup and the log area no longer contains all the required redo log entries, for example because they were damaged, you also need the log backups since the last data backup.
More Information