Complete Guide For SQL Server Database Integrity Checks

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Written By Ashwani Tiwari
Anuraag Singh
Approved By Anuraag Singh
Published On December 6th, 2023
Reading Time 5 Minutes Reading

In these days, people have numerous databases in their SQL Server. So, there are chances that they face SQL Database integrity issue while working with the multiple SQL databases. Due to the huge amount of data, SQL Server become vulnerable to corruption. So here we will discuss some SQL Server Database integrity check.

Solution for SQL Server Database Integrity Checks

In order to check SQL Server database integrity problem, database administrator executes the DBCC (database console commands) statements. You may or may not have heard about this command but it is used to perform the operation like Maintenance, Miscellaneous, Informational, and Validation. However, for checking the logical or physical integrity of the SQL Server database, it is required to run CHECKDB command.

There are following operations that are performed by using the CHECKDB command:

  • DBCC CHECKALLOC– It checks the consistency of disk storage structure for a particular database.
  • The CHECKTABLE – This DBCC CHECKTABLE command is used to check the SQL Server database integrity of all the pages & structures that manage the view of table or index.
  • DBCC CHECKCATALOG – It executes to check the consistency within the particular database.
  • The CHECKDB – This is used to check the catalog consistency in the specified SQL database.

Syntax of DBCC CHECKDB

DBCC CHECKDB

What is the Objective of the DBCC CHECKDB?

There are mainly two roles of DBCC CHECKDB command. The first objective is to check SQL Server database Integrity and the second is to correct the errors.

Integrity Check:

The DBCC CHECKDB command follows a few steps on its execution for SQL Server database Integrity checks.

  • Verify the allocated structures such as GAM, SGAM, PFS, IAM
  • Verify the table consistency and its all indexes.
  • Finally, verify all the system catalogs.

Correction:

Once you have checked the SQL database and noticed that integrity has not been maintained. Then, you need to correct all the possible damaged or distorted pages. The DBCC CheckDB itself can fix these damages.

The “REPAIR_ALLOW_DATA_LOSS” option changes the corrupted page for a new one. By using this command, you can save the integrity of the SQL Server database. But, you should keep in mind, we are only talking about the physical structure, not about the internal data integrity.

Another option to correct the SQL Server database integrity is “REPAIR_REBUILD” command. It is used to correct the problem in non clustered indexes. With the help of this option, we do not lose the data items.

Process to Execute CHECKDB Command

If talking about the process to execute the CHECKDB command, it does not directly run on the SQL database. For running the command, it creates a hidden database snapshot and the command runs based on this snapshot. But, most of the people realize this only when CheckDB command denies executing and once they start searching on it, they find out about “some snapshot” that failed the creation. In this situation, you will definitely want to what to do if the snapshot creation fails? There are three options for this. You can choose any of these:

  1. Fix the permission to create the hidden snapshot.
  2. Execute the DBCC CHECKDB with the TABLOCK option. This can bring problems, as the database will be a target of locks.
  3. Create a process by following these steps:
    • Create a snapshot of the database.
    • Run the DBCC CheckDB command on this snapshot.

Limitations of SQL Server Database Integrity Checks Command

Even though, DBCC CHECKDB command maintains the SQL Server Database integrity, there are few limitations like it will not able to repair the major issues in SQL database integrity. Also, system tables and data purity detected errors cannot be resolved by using DBCC CHECKDB command. SQL database should be on SINGLE_USER mode to perform the correction by using DBCC CHECKDB command.

When CHECKDB Command Does Not Work?

If DBCC CHECKDB job failed to maintain the Microsoft SQL Server database integrity check, you can use the SQL Database Recovery Tool as an alternate option. This software has the facility to maintain both internal and external integrity after performing the recovery process. It scans your database and find out the issue and recover it simultaneously. Apart from this, there are several features provided by this professional tool which makes it different from others. This application can easily remove the corruption from the SQL database. But also provides you advanced features like the user can recover deleted SQL table database objects. Moreover, this application supports Latest SQL Server 2019 / 2017 / 2016 / 2014 /2012 and its below versions.

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Bringing It All Together

SQL database plays an important role in any organization. There are many reasons that can affect the SQL Server database integrity, so you must check SQL Server database integrity on the database. Hence, we have discussed the DBCC CHECKDB command to perform SQL Server database integrity checks whether it is maintained or not. If it does not maintain, the command will correct the issues. But, in the case of a major problem, it is advised to use SysTools SQL Database Recovery software.

Frequently Asked Questions

What is database integrity in SQL Server?

Data integrity refers to the accuracy and consistency of the data.

Is there any bad affect using DBCC CHECKDB?

Generally, there is no such effect on your SQL database while checking database integrity. But it will not able to repair the major issues in SQL database integrity.

Can we repair the database with DBCC CHECKDB “REPAIR_ALLOW_DATA_LOSS” command?

Yes, But Repair_Allow_Data_Loss is not considered the best option. Because the execution of this command is not highly supported because it may cause data loss issues.

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By Ashwani Tiwari

Being a Chief Technical Analyst, I am aware of the technicalities faced by the user while working with multiple technologies. So, through my blogs and articles, I love to help all the users who face various challenges while dealing with technology.