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:

<code class="sql">ROLLBACK;</code>

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:

<code class="sql">ALTER DATABASE FLASHBACK ON;</code>

Execute Flashback query:

<code class="sql">SELECT * FROM table_name AS OF TIMESTAMP TO_TIMESTAMP('2023-03-08 10:00:00');</code>

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:

<code class="sql">expdp user/password directory=DIR dumpfile=dumpfile.dmp</code>

• Then, import the export file:

<code class="sql">impdp user/password directory=DIR dumpfile=dumpfile.dmp</code>

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.

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