Encountering database corruption in SQL Server is a nightmare for database administrators. There are many reasons why database corruption usually occurs. With this write-up, we will learn more about SQL database corruption, common causes for database corruption, and the best ways to resolve corruption without compromising data integrity.
Before proceeding with the causes and solutions, let’s first take a look at a user query to understand what kind of messages a user or database administrator can come across due to database corruption.
Let’s Talk About SQL Server System Database Corruption in Detail
“I had a data file & I wanted to attach that MDF file to MS SQL Server 2014. Whenever I try to attach this file, I always receive the following error message:
The header of the file ‘…/MSSQL/DATA/yyyy_data.mdf’ is not a valid file header of the database. It also displays that the FILESIZE property is incorrect. After searching through the net, I found that the MDF file has corruption in its header part. I tried various expert solutions from various forum sites to solve it but I failed, and thus I am getting the same error message again & again. I would like to know that, what are the reasons for this database corruption in SQL Server. Any help will be highly appreciated. Thanks!”
As we saw in the above-mentioned user query, the user or database administrator has encountered an error message for database corruption. We will now understand what exactly database corruption is and how it affects users. In SQL Server databases, when one or more than one database components get damaged for any reason, it can result in database corruption. There is no specific cause for database corruption; however, due to database corruption, SQL Server becomes prone to encountering various errors like Microsoft SQL Server header error 5172, SQL Server Error 2, and SQL Server Error 5171. We will now take a look at some of these common causes for database corruption and how it can be prevented.
Understanding SQL Database Corruption Causes
Below are some of the triggers for SQL Server corruption in the database:
- Hardware failures are one of the most common causes that corrupt or damage the database or database objects in SQL Server.
- Sudden power failures or improper shutdowns in the database can interrupt write operations in the database, further leading to corruption as well.
- If there is a problem with the Windows file system, disk space insufficiency, or storage device failures, it can also lead to database corruption.
- Due to malware and ransomware attacks on the database, the malicious software can delete, modify, or manipulate data. Furthermore, ransomware attacks can also damage the database, leading to possible corruption.
After knowing the common causes, let’s now move to understanding the methods to repair SQL database corruption.
Manual Technique to Fix SQL Server Database Corruption
The below-stated techniques can be used only for minor-level corruption; hence, it is suggested not to expect immediate results. This method only depends on the level of corruption, since it is no more effective to deal with a certain level of corruption. Users can follow some of the manual methods to resolve SQL Server data corruption:
- To fix the issue, one can use log file or a backup file to repair the SQL Database, but in some of the cases, due to the high corruption, this method may also not work.
- The user can also try the database console commands DBCC REPAIR and DBCC CHECKDB to fix SQL database corruption; this particular method requires a lot of technical knowledge & grip on commands. It is thus suggested that non-technical users should not go for this solution. This method is only useful in case of minor-level corruption.
Important: While executing DBCC CHECKDB commands, if the user doesn’t pay attention to the technicalities, they can lose data permanently.
How to Fix SQL Server System Database Corruption Professionally?
There are a few manual methods available to repair SQL database corruption, but they require all users to have technical expertise, as incorrect execution of the commands can risk data security. To prevent such issues, users can try dedicated solutions like SysTools SQL Database Recovery Software to repair corrupt SQL database files(MDF & NDF).
It helps users to recover & restore triggers, rules, tables, functions, stored procedures, etc. The understandable user interface of this tool makes it simpler to recover various other SQL objects present in MDF & NDF files in a hassle-free way. The tool is also capable of recovering data from ransomware- or SQL injection-affected database files.
Steps to repair SQL database corruption are as follows:
Step 1: Launch the software to repair & open MDF file. 
Step 2: In the Scan Options, you can select any one according to the need. After that, select the SQL Server version. 
Step 3: After scanning the MDF files, click on the database objects to preview the recovered database.
Step 4: The software allows you to export the recovered MDF file in the following formats:
- SQL Server Database
- SQL Server Compatible Script
- CSV File Format
Step 5: Next, choose one from the ‘With the only schema’ & ‘With Schema & Data’ options according to users’ requirement. Lastly, click on the Export button.
Prevention Tips for SQL Server Database Corruption Issues & Errors
- Don’t Reboot Server: By rebooting the server, you can only help & fix minor issues from the Operating system’s end. If there is an issue from the server’s end, then rebooting is not at all an appropriate means of solving SQL Server data corruption. Rebooting the system will only transfer the database in offline mode & will detect the database in SUSPECT mode. This can even lead to a worse situation.
- Don’t Shut Down Server: Once identifying the master database corruption & repair SQL Server master database, every user tries to shut down the Server, which is not an appropriate solution, as it may make the database inaccessible.
- Don’t try to Detach / Reattach Database: If the SQL database is corrupted, then reattaching & detaching the database will make the process even worse.
- Don’t Upgrade SQL Server: Do not upgrade the server to repair SQL database. As it is not an accurate method because updating or upgrading the version will only create new hurdles.
- Don’t Run Any Repair Commands: The DBCC CHECKDB command should not be run unnecessarily. If all other methods fail to work, then the user should opt for this manual way. In many cases, this command results in permanent loss of data. Thus, while executing this command, you should be technically strong & have knowledge of its correct syntax.
Final Note
In this article, we have discussed SQL database corruption causes such as power failure, sudden shutdown, hardware failure, malware attacks, etc. Along with the common causes, we have also described the manual and dedicated ways to resolve the issue and the prevention tips for database corruption in SQL Server.
Frequently Asked Questions
Ans: There are many reasons for database corruption, such as:
1. Hardware Failure
2. Software Problem
3. Human Errors
4. Malware or Ransomware Attacks
Ans: DBCC CHECKDB is used to check the corruption in the SQL Server database and to fix minor problems. To check, you can follow the syntax – DBCC CHECKDB (database_name).
Q-3. Is an automated solution safe to fix SQL database corruption?
Ans: Yes, SysTools take care of your data & offers a very secure repair process. The software is smart enough to keep the data safe from all threats.
Q-4. Which solution is best to repair database corruption?
Ans: After studying both methods, experts always prefer the automated solution for the variety of features that they are getting at affordable prices. Moreover, it is a perfect fit for beginners, advanced & expert users.