Accidentally deleting data in a SQL Server database can be a nightmare. However, with the right tools and strategies, it is possible to recover the deleted data. In this blog post, we will explore different scenarios and methods for recovering deleted data in SQL Server.

Scenario 1: Full Database Backup Only

If you have only a full database backup, the recovery process becomes more challenging. In this scenario, you can only recover the data that existed in the table at the time of the backup. Any records inserted or modified after the backup will be lost. To recover the deleted data, you need to compare the records from the backup with the current state of the table and create a synchronization script to apply the changes.

Scenario 2: Full Database Backup with Differential Backups

If you have a full database backup followed by differential backups, the recovery process becomes slightly easier. In this scenario, you can use the full database backup and the most recent differential backup to recover the data. However, any changes made after the last differential backup will still be lost.

Scenario 3: Full Database Backup with Transaction Log Backups

This scenario provides the most optimal recovery strategy with minimal data loss. By having a full chain of transaction log backups, you can recover the database to an exact point in time. However, it is crucial to know the exact time when the records were deleted to restore the database to the correct state. This method requires restoring the full database backup, followed by the most recent differential backup (if available), and then restoring the transaction log backups in the correct order. Once the database is restored, you can identify the deleted records, script them, and apply the script to the original database.

Scenario 4: Recovering Deleted Records without Backups

What if you don’t have any backups or transaction log backups? Is it still possible to recover the deleted data? The answer is yes, thanks to tools like ApexSQL Recover. ApexSQL Recover can read the data pages in the MDF file and create an undo script for the deleted records. However, the longer you wait to recover the data, the higher the chances that the deleted records will be overwritten and permanently lost. It is recommended to create a copy of the MDF and LDF files immediately and run ApexSQL Recover on them.

Using ApexSQL Recover

To demonstrate how ApexSQL Recover works, let’s consider a scenario where records are accidentally deleted from the Person.EmailAddress table in the AdventureWorks database. Here are the steps to recover the deleted records using ApexSQL Recover:

1. Delete the records from the table using SQL Server Management Studio or a script.
2. Launch ApexSQL Recover and select the “From DELETE operation” option in the Recovery tab.
3. Select the SQL Server instance and the database.
4. Choose the appropriate option based on your transaction log backups.
5. Specify the time range for the deletion.
6. Select the tables to recover the data from.
7. Choose whether to create a recovery script or a new database with the recovered data.
8. Review and execute the recovery script.

ApexSQL Recover will analyze the MDF file, identify the deleted records, and generate a recovery script. You can then review and modify the script if needed before executing it. Once the script is executed, the deleted records will be recovered.

ApexSQL Recover is not limited to recovering data from DELETE statements. It can also help recover data lost due to DROP TABLE or TRUNCATE statements, as well as repair corrupted MDF files that cannot be attached to a SQL Server instance.

Conclusion

Accidental data deletion in SQL Server can be a stressful situation, but with the right tools and strategies, it is possible to recover the deleted data. By having a solid backup and recovery strategy in place, you can minimize data loss and ensure the integrity of your database.

Disclaimer: The information provided in this blog post is for educational purposes only. Always consult with your database administrator or IT professional before making any changes to your production environment.