How to restore database from ldf file sql server 2008 using lsn

LDF files are the SQL files created by SQL Server which contains the logs or transactions occurred in a Relational Database Management System (RDBMS). Logs or transactions are the recent actions or commands executed in a database, which are used to track events so that data can be recovered from unexpected system failures or power supply cut-off. These logs contain a history of activity for both fully committed and partially committed transactions to the database. When the user is not able to access his data, he can restore database from LDF file by using the method mentioned in the article. Along with this the user can also try a third party utility namely SQL Server transaction log viewer.

As we already know about LDF file created by SQL server. Every record in a database is first stored in LDF file. In LDF file, an LSN(Log Sequence Number) is assigned to every record. The LSN of a log record at which a significant event occurred can be useful for constructing correct restore sequences and they store enough information to restore database from LDF file (transaction log file) to a specific point in time, to replay or undo a change. Problems faced while accessing SQL Server files

1. The memory disk system may get affected due to several reasons which may affect the arrangement of table details in the database. Ultimately, you will not be able to access the data. In this case, restoring SQL Server databases from LDF files will be the most effective solution to restore database from LDF file.

4. The Power failure is the most common cause of data corruption. Suppose a person is inserting some data into the database and suddenly power cut off, then the address of the next record is likely to be lost, which ends up in a corruption. Then logs can be used to restore database from LDF file. How to Restore SQL Server Databases from LDF Files

• First of all, we need SQL ServerTransaction Log to restore database from LDF file by using LSN.SQL ServerTransaction Log will provide information about the deleted rows.We need to run fn_dblog() function that will provide the information about the transactions.

• Now, we can see the deleted transactions under Transaction ID column which we will use in the below statement to get the LSN of the LOP_BEGIN_XACT operation. That means we need the exact LSN when the DELETE statement began its transaction.

Now run a transaction log backup on the database where the data was deleted if a transaction log backup has not run since the data deletion. Next, we will restore this database here else or on the same server with the different name until the above LSN and then we will import the deleted data from newly restored database to your production database

The above-mentioned methods for restoring SQL Server databases from LDF files are tedious and can be done if you have knowledge of SQL Server. So, it is better to use automated tools which are easy to use and affordable. The advanced scanning option of SQL recovery software will restore the database from LDF file and the online and offline option of SysTools SQL Log Analyzer will allow the user to recover database from LDF file.