How to completely repair MDF files in SQL Server database-headlines-php.cn

As we all know, database files store a large amount of important information, so they are crucial to all users. Let us learn how to repair damaged SQL database files through manual and professional methods.

Microsoft's SQL Server is now one of the most commonly used relational databases. Due to its advanced internal structure and high reliability, most organizations choose SQL Server database to store all business-critical data. But sometimes, conditions such as virus infection, operating system failure, file system corruption, etc. can cause the SQL database to be damaged, so that all the data stored in it becomes inaccessible. However, in real scenarios, it is not an easy task for us to repair various .mdf files in a damaged SQL Server.

General users can gradually repair damaged MDF files in SQL databases through manual methods, but this method is not reliable because it cannot guarantee that the data can be completely restored. However, there are also third-party tools like SysTools SQL Recovery that claim to be able to repair .mdf files in a perfect way.

So in this article, we will discuss with you the best solutions to repair a damaged SQL database. But before we start, let us first understand the reasons behind the corruption of SQL database.

Causes behind SQL database damage

There are many reasons behind SQL database damage. As we all know, each MDF file of a SQL database is actually some major database files, which store all users' data, so the corruption of any MDF file may cause the entire database to collapse. It can be seen that we need to first understand all the possible reasons behind the damage of MDF files:

The storage medium where the .MDF file is located is damaged.

.If the user stores the SQL database in a compressed folder, the MDF file may be damaged.

.Any modifications or changes made under a certain SQL Server account.

.A user may delete data by mistake.

.The MDF file is damaged due to the damage of the file header.

.The disk drive is damaged.

If a network failure occurs when the .SQL database is being written and used, the MDF file may be damaged.

. Other possible causes of MDF file damage include: virus attacks, hard drive failures, abnormal system shutdowns and sudden power outages, etc.

So, if the MDF file gets corrupted, then the SQL database becomes inaccessible. Additionally, users may see error messages if they attempt to access a corrupted database. Below we have listed some of the most common error messages:

Corruption of the storage medium where the .MDF file is located.

.If the user stores the SQL database in a compressed folder, the MDF file may be damaged.

. Metadata corruption error.

.Users may delete data by mistake.

.Msg 823/Msg 824/Msg 825 (read retry) errors in SQL Server.

In addition, users may also encounter other types of error prompts when accessing damaged SQL databases. As can be seen, database administrators should take immediate steps to prevent any type of data loss.

How to manually repair MDF files

We can use several manual methods to repair a damaged SQL database, but these manual solutions cannot guarantee that the database can be fully restored.

Users can use SQL Server's NDF files (some log files) for recovery. But in most corruption cases, log files alone are not enough to restore the database. Because sometimes in some cases that are severely damaged, the corresponding backup files are also damaged.

Another possible way to repair and restore a damaged SQL database is to use database console commands, such as: DBCC CHECKDB. This command is very effective in repairing minor corruption issues in SQL Server databases.

Steps to use DBCC CHECKDB to repair damaged MDF files

First, you need to run DBCC CHECKDB on the damaged SQL database, please execute the following command:

1.DBCC CHECKDB (Name_of _corrupt _database)

Note: You can also define option parameters such as no_infomsgs and infomsgs for DBCC CHECKDB.

After this, you need to start checking the index ID.

Case 1: If the index ID>1, discard it immediately and recreate it.

Case 2: If the index ID is 0 or 1, run DBCC CHECKDB again using the appropriate repair options, such as repair_rebuild, repair_fast, or repair_allow_data_loss.

DBCC CHECK (name_of_corrupt_database, repair_fast)
DBCC CHECK (name_of_corrupt_database, repair_rebuild)
DBCC CHECK (name_of_corrupt_database, repair_allow_data_loss)

At this point to ensure that all damage has been repaired, run DBCC CHECKDB again. If it shows 0 allocation errors and 0 consistency errors in name_of_your_corrupt_database, you're done.

What if the manual method fails?

Due to its own limitations, manual workarounds are not always foolproof. For example, when an MDF file is severely damaged, manual repair often ends in failure. Moreover, manual solution methods require users to have strong technical skills. Therefore, we recommend using some reliable third-party software to repair damaged SQL database. SQL Database Recovery Program is the best utility that can repair any type of corruption issue in MDF files.

SQL recovery tool can repair both MDF and NDF damaged SQL database files. It is a risk-free software that can recover all data items stored in various tables, rules, triggers, and functions. Apart from this, you can complete the database repair with just a few clicks of this software without wasting any time.

Specific steps to repair damaged MDF files

Download and run the SQL recovery program on your local machine.