In the absence of the correct technique, it is too difficult to repair a corrupt SQL Server database. You can manually repair SQL database but professional solutions are highly trusted and safe to do this. There are lots of professional tools available in the marketplace but finding the best one is mandatory. Before we pick the solution to fix SQL database corruption, know about SQL Server and the causes for its corruption.
About SQL Server
SQL Server is a database management system used to store and extract data by other applications. It is developed by Microsoft and works on three different file types to manage and store data – MDF (primary files), NDF (Secondary files), and LDF (Log files).
MDF: These are primary files and they can store objects including columns, views, indexes, tables, keys, functions, triggers, default values, etc. Each database has a primary file and MDF files save startup details of the database.
NDF: These are secondary files and you can freely create any number of NDF files as per your needs. These files are mainly used to spread data to multiple disks and also for storing data.
LDF: These are backup files of SQL Server and you can use them to restore the database in situations of file corruption. Every database has at least a single log file.
Causes for SQL Database Corruption
There can be various reasons that can corrupt a SQL database. Let us check out the reasons for MDF file corruption:
- Bugs in disk drivers
- Network failure when the database is in working condition
- Accidental deletion of data
- Changes in SQL Server account
- Storing SQL database in compressed folders
- Corruption in storage media where MDF files are located
- Power failure, hard disk failure, system shutdown, virus attacks, etc. are other reasons for the corruption of MDF files in SQL Server.
Corruption of MDF files throw various errors like:
- Error 9004
- Corruption in data pages
- SQL Server Table corruption error
- Metadata corruption error
- SQL Server page-level corruption
- Msg 823/Msg 824/Msg 825 errors in SQL Server
Things to avoid when you encounter SQL Server Database Corruption
Do not restart SQL Server: While working on SQL Server, when you face some interruptions, don’t restart your server without saving the data. This will corrupt the SQL database and give birth to many errors in your SQL database.
Do not detach the database: Trying to detach the SQL Server from the database may damage or corrupt the database.
Do not shut down the server: While working on SQL Server, when you suddenly shut down your system, it may harm your database in SQL Server.
Also read: How to Fix Corrupted Access Database
How to detect SQL Database Corruption?
The database administrator looks after the security and availability of the database. Sometimes when you face corruption, you can’t get any errors but the data remains unavailable. Therefore, the administrator performs some tasks to check the database to find errors or corruption.
Run CHECKSUM Command: During the backup process, the admin should include the CHECKSUM command which will check the database for corruption and stop the backup when there is corruption.
BACKUP DATABASE ABC
TO DISK = ‘E:\Database Backup\ABC.bak
WITH CHECKSUM;
Run DBCC CHECKDB Command: This command is just a routine command to detect various issues in the database.
DBCC CHECKDB
This command will check the integrity of the database including objects such as triggers, tables, relationships, dependencies, etc. In case it finds any issue, it will show the error message with the result.
Methods to Repair a Corrupted SQL Database
You can use SQL Server Management Studio or a specialized program to repair a corrupt SQL database. Let us know both solutions one by one.
Method 1. Using SQL Server Management Studio (SSMA)
To use this method, you need to use various database console commands – DBCC CHECKDB and DBCC DBREPAIR.
Note: Before you start the process, kindly note that this method only deals with minor corruption. For severe corruption, go for an automated program.
- Launch SQL Server Management Studio on your system. Make sure the corrupted database file does not open anywhere.
- Go to the toolbar, here you will see a New Query button. Click on it to go to the new query page.
- On the opened page, write SQL scripts (mentioned below). Use the original name of the database in place of text (YourDatabase).
ALTER DATABASE (YourDatabase) SET EMERGENCY
DBCC CHECKDB (your database)
ALTER DATABASE (YourDatabase) SET SIGLE_USER WITH ROLLBACK IMMEDIATE
DBCC CHECKDB ((YourDatabase) REPAIR_ALLOW_DATA_LOSS)
ALTER DATABASE (YourDatabase) SET MULTI_USER
Now, hit Execute to start the repair process for the corrupted SQL Server database.
Method 2. Professional Software to Recover a Corrupted SQL Database
If you can’t repair an SQL database manually, you should try a professional tool i.e. Softaken SQL Recovery Software. This software smoothly fixes minor as well as major corruption issues of SQL Server database. This advanced solution will not disappoint you and perform successful recovery of SQL Server MDF & NDF files. It is capable of restoring all objects like keys, indices, rules, tables, defaults, etc., and saving them to a new SQL database file.
The best part is this utility can consider multiple SQL database files to repair in a single attempt. It also displays the recovered data in the preview pane before saving it. To check this application, you can install the freeware edition and after satisfaction, you can purchase the licensed version.
Know the steps to Recover a Corrupted SQL database
- Install and launch the software to repair the SQL database.
- Now, browse the affected SQL database files.
- Get the preview of the repaired SQL file.
- Specify a path to save the new data file.
- Finally, hit the ‘Repair’ button and after a few minutes, you will get a new SQL file where all data of the corrupted SQL file is saved.
Conclusion
A lot of techniques claim to repair a corrupted/damaged SQL database. However, not all can restore all objects from corrupted SQL Server database files. But using the methods mentioned in this post, you can smoothly recover corrupted SQL files. The manual way might fail in dealing with major corruption issues but the automated program will surely help to restore all data from corrupted SQL database files.