recover deleted data from sql log file

Recover SQL Log Deleted Data

Summary: Discover easy steps on how to recover deleted data from SQL log files and the SQL Server, safeguarding your critical information. All the necessary tools are available on this blog for users to review their files, To get the best results, subscribe to the blog!

How to Recover deleted data from SQL log file will require a few steps. To stop additional changes to the log file, shut down the SQL Server first.Next, identify which Log Sequence Number was most recently removed.This can be accomplished by tracking log updates with the help of the fn_dblog function.Restore the log backup containing the deleted data after acquiring the LSN.

We’ll use this technique to recover the log entries from before they were removed. You can use SQL queries to recover the deleted data from the restored log after restoring the log backup. Make sure to check the recovered data for accuracy and make any necessary database modifications.

Why Deleted Records in SQL Server Need to Be Recovered by the User?

For a variety of reasons, users frequently need to recover lost records in SQL Server.

  1. Accidental Deletion: To preserve data integrity, users may unexpectedly erase vital data, including customer or business records. The data is restored in this instance.
  2. Data Recovery:  It may be necessary to retrieve important data from deleted records to maintain business operations or comply with legal requirements.
  3. Historical Analysis: to perform historical analysis, reporting, or trend analysis, it could be necessary to recover deleted records.
  4. Data Audits and Forensics: In situations where these services are essential, recovering deleted documents can provide information about unauthorized access or malicious behavior.
  5. Data Restoration: Recovering erased records may be a component of a larger data restoration procedure following a data loss, corruption, or system failure event.
  6. Maintaining data integrity: involves backing up accidentally deleted records from the database to ensure consistency and reliability.

In the upcoming section, we are going to discuss manual solutions to recover deleted data from SQL Server table by transaction logs.

How Can Delete Records in SQL Server be Recovered Manually?

The presence of your data.bak file is crucial when thinking about a manual method to recover deleted rows from the SQL Server database. Periodically discussing a proper backup of your SQL Server database will assist you in learning how to remove data in SQL with ease. This method also applies to objects, records stored procedures, and SQL database functions.

Because differential backups aren’t always helpful, there are requirements for your solution as well. You now require the complete backup of your SQL database to carry out some of the possible manual options. Once you have the necessary files, proceed with the instructions.

  1. Restore the SQL database. bak file.
  2. Locate the deleted data from the file. Bak.
  3. Maintain separate copies of both databases.
  4. Apply the UPDATE function to modified records.

Does your System Operate in Either locked or Full Recovery Mode?

This is an open-ended inquiry. This recovery mode determines your chances of getting your deleted rows or data back. It is necessary to have full recovery or bulk-locked recovery mode enabled in the SQL server to manually retrieve deleted records using a Log Sequence Number. Those with a reasonable level of proficiency with SQL technicalities might easily handle every problem, however First-time users may encounter certain difficulties. Users must never neglect the prerequisites for SQL Server recover deleted records procedure. As a result, specialists advise against using this method for everyone.

Also Read SQL Server Security Best Practices without any issue.

How to Use Log Sequence Numbers to Restore Deleted Records in SQL Server

To successfully learn how to recover deleted data from SQL log file. using an LSN, there are specific processes that must be followed. The first step in any restoration process is to locate the exact record that was erased together with the table that goes with it. You can identify the precise LSN associated with the delete operation in the transaction log by using the `fn_dblog` function. This serves as a unique identifier for the location of the deletion.

Transaction log backups up to the designated LSN and entire database backups are applied after obtaining the log sequence number in order to initiate the restoration process. This sequential backup program essentially restores the database to its pre-deletion state, guaranteeing a consistent point-in-time recovery.

Recover Deleted Data from SQL Server Table by Transaction Logs  Using LSN Method

Using the techniques listed below, you can accurately restore deleted data in SQL Server 2019, 2017, 2014, 2018, and 2005.

These are the steps to recover deleted records in SQL Server

1. Verify how many rows in the table with deleted records are active.

SELECT FROM Table _name  

2. Take a log backup now.

USE DatabaseName
GO
BACKUP LOG [DatabaseName]
To Disk = N’D: \DatabaseName\ RDDTrlog .Trn ‘
WITH NO FORMAT, NOINIT,
NAME = N’ databaseName - Transaction Log Backup ‘,
SKIP NOREWIND, NOUNLOAD , STATS = 10
GO

3. Get the deleted records’ transaction ID.

USE DatabaseName 
GO
Select [Current LSN, LSN], [Transaction ID], Operation, Context, AllocUnitName 
FROM
Fn_dblog (NULL, NULL)
WHERE Operation = ‘LOP_DELETE _ROWS

4. Knowing when the rows were deleted helps find them in SQL Server using transaction IDs, which are like markers in a log, helping to recover deleted data effectively.

USE DataBaseName 
GO
[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’

5. Start restoring deleted data from SQL Server table records

Recover Deleted D USE DatabaseName
GO
RESTORE DATABASE DatabaseName_COPY FORM
Disk  = ‘D: \DatabaseName \RDDFull.bak’
WITH
MOVE  ‘DatabaseName ‘ TO ‘D:\RecoverDB\DatabaseName.mdf’,
REPLACE, NORECOVERY;
GO

6. Check the table one last time to see if the deleted rows have been recovered.

USE DatabaseName_Copy GO Select * from Table _name 

An Alternate Method for SQL Server Record Delete Recovery

The best solution is available to retrieve the rows from SQL Server 

2020, 2017, 2016, 2014, 2008, and 2005 This alternative solution can correct SQL errors and database files such as primary MDF and secondary NDF files. It can also fix any kind of problem that comes up with SQL Server. An automated tool SysTools SQL Transaction Log Analyzer Tool makes it possible to retrieve deleted tables, triggers, rules, and other data.

Steps to follow to recover deleted SQL Records

  1. Launch the program and open the MDF file after downloading the software.
  1. To recover deleted records in SQL Server, select the Advance option and find the version of SQL Server.
  1. The solution will initiate the primary database file (MDF) scanning process.
  1. When using the preview SQL database components tool. the Deleted SQL table records are displayed. Click the export option after that.
  1.  Details about the database must be provided in the next section.
  1. Select the option to Create a new database and provide the database name.
  1. To restore data from deleted rows in the SQL Server, export the database containing the schema and data.
  1. After saving the report, access the recently made database that has the recovered records in it.

Conclusion:

Hopefully, you have received your response. Because the solutions discussed in the blog will help you how recover deleted data from the SQL log file Server, the manual, as well as automated applications we have discussed in this article, will help you resolve the issues. Moreover, it is a write-up that solves the problem step-by-step if you follow the instructions. I hope this post will explain how to use it for you.

ReadMore: Unlocking the Power of SQL: Why You Should Take a SQL Course

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