Ultimate Guide On How to Recover Deleted Data from SQL Log File

If for any reason – some table records get deleted from the database then, no need to worry about it. With the right solutions for how to recover deleted data from SQL Log file, it is possible to rollback and retrieve deleted data from SQL Server. However, with management studio, the entire SQL data recovery from log files becomes cumbersome. Therefore, in this article, we are going to provide solutions that let you recover deleted data from SQL Transaction Log files.

Let’s first take a look at the causes of how the records in the SQL database get deleted.

Causes for Data Deletion In SQL Server

In the SQL Server database, there are various reasons that can eventually result in the deletion of the data. This deletion can be unintentional or intentional. Here we will look at some of the reasons that might result in the deletion of the data and then we will look at the solutions on how to rollback deleted data in SQL. 

Accidental Deletion

This is one of the most common causes for the deletion of data in SQL Database. Due to human errors like not using proper commands, they might end up losing the records in the database. After the accidental deletion, it becomes important to know the methods for how to recover deleted data from SQL Log file. 

Software or Application Bugs

Another cause for the deletion of data in the SQL Server Database is due to software bugs. The bugs in the applications can lead to the deletion of the data without the user’s information. 

During the Database Maintenance

Sometimes, the database administrators plan a maintenance schedule for the SQL database. Most of the time during the scheduled maintenance, the data gets deleted without a proper check resulting in the loss of any necessary data from the database. 

Malicious Attacks 

Like other causes for the record deletion, unauthorized access to the database or any kind of insider threats can also lead to the intentional deletion of data in the SQL Server database. 

All these factors are possible causes for the deletion of data in the SQL Server database. To resolve the issue of how to recover deleted data from SQL Log file, we will now try and understand a few solutions.

How to Rollback Deleted Data in SQL Server From Log File?

As there are various causes for the deletion of data in the SQL Server, we have different solutions that will help the users recover the data more efficiently. We will discuss these solutions one by one to understand them. The first solution we are going to try is the recovery using the LSN Method.

Recover Data After Deletion In SQL Server Using LSN

LSN stands for Log Sequence Number. Each transaction in the SQL Server is given a unique log sequence number. The LSN helps the users to trace any transaction like deletions and also with the recovery of those transactions in case of accidental deletions. The steps to recover deleted data are as follows:

1. To check the number of rows in the table from where the records are deleted, use the command given here:
   SELECT * FROM TABLENAME
2. Now, to take the backup of the log, use the following command:
   USE DATABASE_NAME
   GO
   BACKUP LOG [DATABASE_NAME]
   TO DISK=N’D:\DATABASE_NAME\RDDTrLog.trn’
   WITH NOFORMAT, NOINIT,
   NAME= N ’DATABASE_NAME – Transaction Log Backup’,
   SKIP, NOREWIND, NOUNLOAD, STATS = 10
   GO
   
3. To retrieve the Transaction ID of the deleted records, the following command will be implemented:

   USE DATABASE_NAME
   GO
   SELECT [CURRENT LSN], [Transaction ID], Operation, Context, AllocUnitName
   FROM
   fn_dblog(NULL, NULL)
   WHERE Operation = ‘LOP_DELETE_ROWS’
   

   This command here will help the users identify the deleted records by providing the entries of transaction logs of the deleted records and offer a solution to how to recover deleted data from SQL Log file.

4. To check the exact time at which the records were deleted, a user can use the command:
   USE DATABASE_NAME
   GO
   SELECT [CURRENT LSN], Operation, [Transaction ID], [BEGIN TIME], [Transaction_NAME], [Transaction SID]
   FROM
   fn_dblog(NULL,NULL)
   WHERE
   [Transaction ID]= ‘000:000001f3’
   AND
   [Operation] = ‘LOP_BEGIN_XACT’Here you are required to enter the transaction ID as it will help you get more accurate results for how to rollback deleted data in SQL.
   
5. The given command will help you to rollback deleted data in SQL Database and resolve the issue of how to recover deleted data from SQL Log file.
   

   RECOVER DELETED D USE DATABASE_NAME
   GO
   RESTORE DATABASE DBNAME_COPY
   FROM
   DISK = ‘D: \DATABASE_NAME\RDDFull.bak’
   WITH
   MOVE ‘DATABASE_NAME’ TO ‘D: \RecoverDB\Database_Name.mdf’’,
   MOVE ‘DATABASE_NAME_Log’ TO ‘D:\RecoverDB\Database_Name_Log.ldf’,
   REPLACE, NORECOVERY;
   GO
   

   This command will help you to recover the deleted records from the database backup file.

By following these steps, one can retrieve the deleted data from SQL Database. The method will help the users to get the data back from the SQL log file. But as we can see this method can be quite complex for users who lack proper technical knowledge, so this is where a professional solution comes to the rescue.

Also Read: How to recover records from SQL Server table in a hassle-free way?

Full Guide on How to Recover Deleted data from SQL Log file in SQL Server 2008 or Above Versions

We cannot afford to lose any records during recovery from a manual workaround. So, it is recommended to use SysTools SQL Log Analyzer. It is the ultimate solution to view the log file of SQL Server and export the deleted records back into the SQL database. It can work without SQL Server application. Let’s understand how this software works and fixes the issue of how to rollback deleted data in SQL. 

Step 1: To restore deleted data of SQL database, you need to add its Log file in the software. So, it can analyze and find all the committed records. To do this, click on Open Button.

Step 2: The solution offers two options to load SQL database – Online DB Option & Offline DB Option.

Online DB Option: This option lets you directly upload the SQL transaction log file from the live SQL Environment. If a user opts for this option, then input the Server name and Authentication type. After establishing the successful connection with SQL Server, choose the database under the Select Database section.

Offline DB Option: This option is beneficial when you do not have SQL Server installation in the system. Here, the user needs to enter the LDF file manually along with the MDF file. In case, the Log & MDF files are available in the same location then, the solution will automatically upload the MDF file just after selecting the Log file. The primary database file is required to read the database schema only.

Step 3: After scanning the log file, the software provides a complete transaction detail along with the Login Name, Time, Table Name, Transaction Name, and Query. Here, you can easily analyze when the delete query runs on the database and fix the ‘how to recover deleted data from SQL Log file’ issue.

Step 4: Click on Export to recover deleted data from SQL Log file.

Step 5: An Export window opens on the screen. Here, check the Delete transaction type under the Export Filters option to resolve the issue of how to rollback deleted data in SQL.

Step 6: Software also provides a Date Filter to export transactions of the particular timeline. Just provide a certain date range in the From & To boxes. Afterward, the solution automatically exports the data according to the provided details.

Step 7: Now, select the location where you want to recover deleted data from SQL Log file. Here, three options are available – SQL Server Database, SQL Server Compatible SQL Scripts, and CSV.

Step 8: Once you select the destination, click on the Export button.

Step 9: After the successful recovery of deleted records from SQL log file, the solution provides you a summary report file that can be saved into the system in CSV file format.

That’s all about how to recover deleted data. This solution helps you in many disastrous situations and performs SQL data recovery from the log files without fail.

With the help of these solutions, one can recover the deleted data in the database. These methods allow the users to understand and resolve the issue of how to rollback deleted data in SQL Server database. 

Conclusion

With the help of this write-up, we understood the causes and solutions to how to recover deleted data from SQL log file. Additionally, to help the users resolve the error efficiently, we have explained different solutions. With the help of these solutions, one can easily understand the possible causes for the deletion of records and then recover them in a hassle-free way.