SQL Server, by Microsoft a prevalent database management system, has a primary function for the applications to store and retrieve data. The data is stored and managed in the SQL Server in three formats: primary files (MDF), secondary files (NDF), and log files (LDF). However, sometimes, they may end up corrupted and in dire need of SQL database recovery.
The.MDF extension is used for primary SQL Server database files. Data and objects are stored in the primary files in each database. Data can be in the form of Values, tables, columns, functions, keys, indexes, default values, and so on. Even MDF files too contain database startup information.
Secondary files are optional and have an extension .NDF. You can make an unlimited number of NDF files based on your needs. Even though these files are mostly used to spread data across discs, they are also used to store user data.
And, sometimes, the SQL server may become susceptible to issues like the corruption of MSSQL databases. If you face the same issue, then let’s unravel how to repair MSSQL Database corruption.
Reasons for MSSQL Database Corruption
SQL Server databases can become corrupted for a variety of reasons. MDF files are the primary database files that contain user data, and their corruption can cause the entire database to be corrupted. MDF corruption can occur for a variety of reasons, including:
- Hardware Problem: Storage media corruption in locations where MDF files are stored
- SQL Malware: SQL database storage in compressed folders
- SQL Server Changes: Changes to the SQL Server account Unintentional data deletion
- Corrupt File: Corrupted file headers
- Driver Flaw: Disk driver flaws
- Network Failure: When the database is operational, the network fails.
- Power Cut: Some of the causes of MDF corruption include hard disc failure, unexpected power failure, unexpected system shutdown, and virus attacks.
SQL database becomes inaccessible in the event of MDF corruption. You may receive an error message while you try to access the corrupt database on your system. Following are the error messages that you might see:
- Data page corruption
- Error Msg 823/ 824/ 825
- Server Table Corruption
- Error in Metadata Corruption
- Page Level Corruption
You may receive various other error messages while trying to work with the corrupt SQL database. However, if you are an administrator on the system, it is necessary for you to act quickly on the error to prevent any data loss. Want to know how to detect and repair MSSQL database corruption? Keep on reading the best way to repair SQL database using DBCC CHECKDB commands as well as with automated solution.
How to Detect MSSQL Database Corruption?
The primary responsibility of the Database Administrator is to keep the database secure and accessible. When database files are corrupted, they may not show any symptoms of error, but the data remains unavailable. As a result, the administrator should use methods that check the database’s health to detect errors or corruption.
Run the database backup in conjunction with CHECKSUM.
When the administrator performs a database backup, the CHECKSUM command should be included with the backup command. If the CHECKSUM command finds any corruption in the database, it will stop the backup process.
DATABASE XYZ BACKUP TO DISK = ‘E:Database BackupXYZ.bak’
Run this command and see the results.
Execute the DBCC CHECKDB command
DBCC is a command that runs a routine database checkup and detects several issues with the database. The command will check the physical and logical integrity of all database objects such as tables, triggers, relationships, and dependencies, and if any problems are discovered, they will be displayed in the result along with an error message. The error message will clearly state the reason for the error and why the process was halted.
How to Repair a Corrupt MSSQL Database?
Repair with SQL Server Management Studio
One of the optional methods for SQL database recovery or repair of a corrupted database is using the SQL Server Management Studio. Do it locally, quickly, and free of charge! However, it is only effective for minor database corruption issues. Since some of the commands make you susceptible to losing data, you may need to lean towards a specialized SQL Database recovery tool.
As a result, let’s go over the basics of attempting to repair or troubleshoot an SQL corrupted database via this method.
Firstly, set your database to EMERGENCY mode. The administrator has read-only access to the database in this mode. To begin, go to Start > All Programs > Microsoft SQL Server > SQL Server Management Studio.
Then, execute the command ALTER DATABASE [database name] SET EMERGENCY.
You can now check the database for errors by running the DBCC CHECKDB (N database name) WITH ALL_ERRORMSGS, NO_INFOMSGS. You’ll receive a report with the found errors and the recommended minimum level of repair. This information can be found at the bottom of the message summary.
Now, you may come across Transact-SQL repair command options at your disposal. The REPAIR_REBUILD command is the most secure option. The REPAIR_ALLOW_DATA_LOSS command is another option. As you might expect, the latter option may result in the deletion of some database pages. As a result, Microsoft does not recommend the latter option unless it is required.
Before attempting repairs, you must first put the database into SINGLE USER mode. This prevents other users from modifying the data during the data restoration. Next, you may leverage the Transact-SQL command- enter the following command:
ALTER DATABASE database_name SET SINGLE_USER.
Now run the DBCC CHECKDB (N ‘database name, REPAIR REBUILD). If the repair was successful, return to MULTI-USER mode. Use the command: ALTER DATABASE database_name SET MULTI_USER.
If you have a severely corrupted database, then this may not be the process for you! So, immediately jump to the next step if you want to repair your database.
Quick Guide to Use MSSQL Database Repair Tool
Using a specialized database repair tool is the best option for repairing a corrupted database. This method is quick, effective, and nearly always complete. Some factors to consider when selecting a SQL repair tool are as follows:
- The tool should work with your SQL version.
- It should have no trouble connecting to your servers and applications.
- The tool should be compatible with your operating system, especially if you’re using an older version.
- It should be demonstrated that it can repair common errors with SQL database
Download the Tool
The kind of tool you want to download and use entirely depends upon you. You may use Stellar Repair for MSSQL which helps in quick and efficient SQL Database recovery software. It is less expensive compared to the alternatives and has a proven record of repairing an array of database corruption. It is simple and effective for minor and major corruption issues.
Apart from resolving SQL database corruption issues, this tool also allows you to:
Retrieve data from damaged/ corrupt MDF and NDF files using scanning algorithms.
- Recover database objects and assist in SML indexes and data types recovery
- Save and recover faster with parallel processing
- Recover deleted table records from the SQL database
- Scan and Recover SQL Database without a lag
- Restore SQL tables with ROW and PAGE Compression
- Configure SQL Database for Windows and SQL Server authentication
Download and install the program with the activation key to have it up and running.
Steps to SQL Database Recovery for Corrupt MS SQL
Step 1: Locate the corrupt SQL database MDF file.
Step 2: Select the SQL database MDF file and then click Repair.
Step 3: Select an appropriate scan mode to repair the file and click OK.
Step 4: It displays the database file repair process’s progress.
Step 5: When the MDF file repair process is complete, click OK.
Step 6: Select Save from the File menu after previewing the recoverable database objects.
Step 7: Click Next after selecting a location to save the repaired SQL database file.
Step 8: Enter the information needed to connect to the SQL Server and save the repaired MDF file, then click Next.
Step 9: Choose a suitable file saving mode and click Save.
Step 10: The status of the file saving process is displayed as Completed, Processing, Pending, or Aborted by the software.
Step 11: A confirmation message is displayed when the saving process is complete.
The Final Thoughts
This blog has covered everything there is to know about SQL databases and their corruption. We discussed what a SQL server is and how a SQL database can become corrupt in the first part using the SQL database recovery process. We also attempted to list all the error notifications a user might encounter while dealing with corruption. This may aid the user in detecting corruption in the future. Finally, we discussed the methods for repairing SQL database corruption. We discussed the best, quickest, and safest method for dealing with SQL database corruption. The tool has an easy-to-use interface and a trial version. I hope you found this blog useful.