Oracle data recovery: How to recover after deletion? If data is deleted during a transaction, the data can be recovered through rollback segments. If the flashback region is enabled, data can be recovered through flashback queries. If you back up your database regularly, you can restore the data from the backup.
Oracle Data Recovery: How to recover after deletion
Direct answer:
After deleting Oracle data, it can be recovered by the following methods:
- Rollback segment: If the data is deleted during the transaction, it can be recovered by rolling back the transaction data.
- Flashback area: Oracle 11g and later provide a flashback area, which stores historical versions of data. If the flashback region is enabled, data can be recovered through flashback queries.
- Backup: Regular backup of the database can ensure that the data can be restored in the event of data loss.
Detailed answer:
Rollback segment
- The rollback segment is used by Oracle Where data changes are saved within a transaction.
- If an error occurs during a transaction, Oracle can use rollback segments to roll back those changes, thereby restoring the data to the state at the beginning of the transaction.
- In order to use rollback segments to recover data, a transaction needs to be opened before the delete operation occurs.
Flashback area
- The flashback area is a special table space that stores historical versions of database data.
- If the flashback area is enabled, deleted data can be recovered through flashback queries.
- Flashback query can obtain data at a specific point in time or version to be restored.
Backup
- Creating a database backup is an important way to protect your data.
- If the data is deleted and cannot be restored using the rollback segment or flashback area, the data can be restored using a backup.
- Backups can be stored on local storage media or in the cloud, and can be created on a schedule or manually.
It is important to note that recovering deleted data is not always possible. If the data is physically deleted, such as using a TRUNCATE or DROP statement, it cannot be recovered by the above methods. Therefore, regular database backups are crucial to ensure data recoverability.
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