How to restore oracle database

Oracle database restore involves rebuilding a corrupt or lost database from the backup or recovery log, including steps such as preparing to restore, recovering data files, opening databases, applying recovery logs, recovering data dictionary, and rebuilding indexes. This process can be automated using Recovery Manager (RMAN).

Oracle Database Restore

Oracle Database Restore Overview

Oracle Database Restore refers to restoring a corrupt or lost database to a specific point in time or state. The restore process involves rebuilding the database using backup files or recovery logs.

Restore steps

Oracle database restore usually involves the following steps:

1. Prepare to restore: Make sure you have the required backup files or recovery logs and close the database you want to restore.
2. Recover data files: Use RESTORE DATABASE command to restore the data files from the backup file.
3. Open the restored database: Use the ALTER DATABASE OPEN command to open the restored database.
4. App Recovery Log: If available, App Recovery Log to restore changes that were not included in the backup file.
5. Recover data dictionary: Use RESTORE DATABASE ... DATA_ONLY command to restore the data dictionary.
6. Rebuild index: Rebuild all indexes and constraints to ensure database integrity.

Restore using RMAN

Recovery Manager (RMAN) is an Oracle-provided tool for managing backups and recovery. The above steps can be performed using the following command via RMAN:

 <code>RESTORE DATABASE FROM '/path/to/backup/file.bak'; RECOVER DATABASE UNTIL CHANGE SCN 'target SCN';</code>

Among them, target SCN is the time point to be restored.

Other precautions

• Backup Policy: Implementing a regular backup policy is critical to ensuring successful restores in the event of a disaster.
• Test Restore: Test the restore process regularly to ensure it is effective.
• Restore to a different server: You can restore the database to a different server than the original server, but the database configuration needs to be adjusted.
• Database Version: The restored database version should match the version used when the backup file was created.

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