How to Prevent Data Loss in Corrupted SQL Server Databases

Microsoft SQL Server is the default database management system of computers running on the Windows operating system. Most of the important information on SQL databases are saved as MDF files. These files can get corrupted and result in data loss unless you fix it quickly.

DataNumen SQL Recovery

Microsoft has developed and released their own database management system that is included in their Window’s operating systems. They call their database server product, Microsoft SQL server.

The primary function of Microsoft SQL Server is to store and retrieve data for other software applications.

What is a MDF file?

Microsoft SQL Server uses the MDF file extension. MDF stands for Master Database File and this is the primary file of an SQL server database. This file contains the main information that is contained in the databases created with this program.

So MDF files are very important for a SQL Database to continue operating correctly, however, MDF files can get corrupted.

How to fix a corrupted SQL Database

1. Use a database console command

  • Execute this query:  DBCC CHECKDB (Name of the corrupt Database)
  • Find the index ID and check that it is correct
    • If the index ID is greater than 1, drop it and create again
    • If the index ID is 0 or 1, execute DBCC CHECKDB again, this time use one of the following repair options:
      • repair_rebuild
      • repair_fast
      • reapir_allow_data_loss
  • After the repair operation has finished, run DBCC CHECKDB again.
  • If you get a “DBCC CHECKDB displays 0 allocation errors and 0 consistency errors in (file name)” the file has been repaired.

2. Use DataNumen SQL Recovery

This is a free data recovery software solution that can repair corrupt MDF databases. The program is designed to recover as much of the data on the file as possible to minimize data loss.

If you are worried that your SQL database has been corrupted, you need to install and run this software. Make sure that, before you use this program, you have closed your SQL Server program and any other application that uses MDF files.

  • Open DataNumen SQL Recovery
  • There will be an option that will ask you to “select MDF/source file to be recovered”. On the box beside it, input the file name. You can also try clicking on the “…” button to look for your file.
  • If you know what the format of the damaged MDF file is, you can specify it in the dropdown menu located to the right of the option “Format”. If you don’t know the format, or don’t feel like specifying that is okay, the program can analyze the MDF file and determine its format automatically. 
  • Click on the “Start Recovery” button.
  • A dialogue box titled “Connect to SQL Server” will appear
  • Set the server name and the authentication for your SQL Server then click “OK”
  • Wait for the program to scan and repair the file
  • The fixed MDF file will be saved using the following format: file name_fixed.mdf.
  • Start the SQL Server program again and try to access the fixed database.

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