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One of the terrible things that every DBA has to deal with is database corruption. Every DBA stores his/her crucial data in the SQL, which size increase with time. Whenever the SQL database gets corrupt, it also damages metadata in the SQL server. Now, fixing this corruption is essential otherwise all the data in SQL would be at high risk.
In this article, we’ll discuss various methods to fix the corruption errors. But, before proceeding to that, let’s gain some knowledge about Metadata, and the reasons behind its corruption.
What is metadata in SQL?
Metadata in SQL is referred to “Information related to other data,” or simply we can say “Data about data.” All information about SQL database can be observed by running sys.databases.
On running sys.databases, some functions in SQL Server will return the information about SQL database. These functions are known as Metadata functions, some of the common metadata functions are:
INDEX_COL, OBJECT_ID, OBJECT_NAME, COL_NAME, DB_NAME, etc.
Reasons behind metadata corruption in SQL
Metadata corruption occurs in SQL database when the system, views, procedures, and functions get damaged. Some other reasons behind the corruption could be:
- Accidental deletion of data.
- Updating software from old version to a newer version.
- Malware/virus attack on the SQL Server.
- Sudden system shutdown or power outage.
- Due to data stored in compressed folders.
Now, all these reasons put metadata in SQL at high risk, so a DBA must take essential steps to get rid of these corruption errors.
How to detect SQL metadata corruption?
Database corruption in SQL can be detected using DBCC CHECKDB. You can run this command to locate errors in the current database. However, to detect corruption metadata, you have to use a different command:
DBCC CHECKCATALOG
This command is used to check and detect corruption in the metadata of SQL. This command checks the consistency of the catalog for the specified database. On running the command, a warning message will appear on the screen displaying corruption in the metadata.
Methods to fix SQL database corruption
Manual methods to fix corruption errors in metadata are limited. The first manual method to save your metadata from corruption is to use backup and restore command. However, this solution is only applicable if you regularly backup your SQL databases. The second method involves fixing the system tables in SQL database in order to fix the corruption errors. To save your SQL database from corruption, follow the below steps:
- Shutdown the server and go to Advanced tab.
- In the configuration manager, add ‘-m;’ to the start of the startup parameter string.
- Start the server again and connect using DAC
However, this is not a reliable solution to fix corruption errors. So, you might use a third-party tool to fix the metadata corruption errors.
Alternate solution – Kernel for SQL recovery
Kernel for SQL Recovery is the best alternative to fix metadata corruption errors. This SQL server recovery tool not only fixes the corruption errors but also restores all the databases objects to the SQL server. Designed with advanced algorithms, it offers some extended features to the users, which include:
- Fix major corruption errors in SQL metadata
- Repair corrupt SQL database files and restore to Live SQL server
- Maintains the integrity of SQL database files
- Restore all database objects like tables, functions, rules, views, indexes, etc.
- Preview the recovered database objects before saving
- Recover multiple SQL database files without any interruption
- Suitable for all versions of SQL server including 2016/2014
These features make Kernel for SQL Recovery one of the best SQL recovery tools. Also, using this tool doesn’t require any specific knowledge, even non-technical users can easily use it.
Conclusion
Metadata is an integral part of each table present in the SQL database. When the database becomes corrupt due to many circumstances, the manual attempt cannot recover the complete data, including metadata. It would help if you used Kernel SQL Database Repair software to recover total database items, including the metadata. You can save the recovered item in a new MDF file.