How to recover deleted data in oracle

Deleted data in Oracle can be recovered through the following methods: undo operation, which is applicable to transactions that have not yet been committed; flashback query, which allows viewing the data status at a specified point in time; flashback table, which restores the entire table to the specified Point in time; data pump import requires previous export backup; manual data repair is complex and time-consuming and requires professional knowledge.

Oracle Data Deletion Recovery

Deleted data in Oracle can be recovered in the following ways.

1. Undo operation (Undo)

• This is the best way to instantly recover deleted data.
• As long as the transaction has not been committed, you can use the undo command to revert changes.
• Syntax: ROLLBACK [TO SAVEPOINT name]

2. Flashback Query

• Allows you to view the status of data at a specific point in time.
• Flashback queries can be used in queries via the AS OF clause.
• Syntax: SELECT * FROM table_name AS OF TIMESTAMP 'timestamp'

3. Flashback Table

• Allows you to restore an entire table to a specified point in time.
• The flashback area must be activated before performing recovery.
• Syntax: FLASHBACK TABLE table_name TO TIMESTAMP 'timestamp'

4. Data Pump Import(Data Pump Import)

• If the database has been exported before, you can use Data Pump Import to recover the deleted data.
• The import must be performed using a user with revoke permissions.
• Syntax: impdp user/password dumpfile=dump_file.dmp

5. Manual data repair

• If no backup or flashback area is available, you can try to repair the data manually.
• Involves extracting data from redo logs or other data sources.
• This is a complex and time-consuming process that requires in-depth knowledge of the database management system (DBMS).

How to choose the appropriate recovery method?

Selecting the appropriate recovery method depends on the following factors:

• Time of data loss
• Importance of data
• Available Backup or flashback area
• Expert knowledge of database management systems

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