How to recover accidentally deleted data in oracle

Oracle data recovery methods: 1. Rollback operation: recent deleted changes can be undone; 2. Flashback query: view and access data at a certain point in the past; 3. Data pump export/import: recoverable Accidentally deleted data a long time ago; 4. Restoring backup: Recover data by restoring backup.

How to recover accidentally deleted data in Oracle

Accidental deletion of data is one of the common problems for database administrators . Oracle provides several mechanisms to recover deleted data.

1. Rollback operation

• If you have recently deleted data, you can try the rollback operation.
• Rollback will undo all changes made since the last commit, including data deletions.
• To roll back, use the following command:

ROLLBACK;

2. Flashback Query

• Flashback query allows you to view and Access data from a point in time in the past.
• To use Flashback queries, you need to enable the Flashback feature, which is disabled by default.

Enable Flashback:

ALTER DATABASE FLASHBACK ON;

Execute Flashback query:

SELECT * FROM table_name AS OF TIMESTAMP TO_TIMESTAMP('2023-03-08 10:00:00');

3. Data Pump Export/Import

• If the data has been accidentally deleted for a period of time, you can use Data Pump export/import to recover the data.
• First, export the data:

expdp user/password directory=DIR dumpfile=dumpfile.dmp

• Then, import the export file:

impdp user/password directory=DIR dumpfile=dumpfile.dmp

4. Restore the backup

• Regular backup of the database is the best method for data recovery.
• If you accidentally delete a previous backup, you can restore the backup to recover the data.
• The process of restoring a backup depends on the backup type.

Notes

• Restoring data may affect database performance.
• Before performing any recovery operations on a production database, testing is highly recommended.
• Back up the database regularly to avoid data loss.

The above is the detailed content of How to recover accidentally deleted data in oracle. For more information, please follow other related articles on the PHP Chinese website!