There are so many facilities and amenities in SQL Server along with built-in methods, which assist users in some bad situations. It is possible that sometimes SQL server put the users in annoying circumstances when it becomes very difficult for them to access the database. At such situations, the very first action performed by SQL users is opting “DBCC CHECKDB” command.
“DBCC CHECKDB” command helps to check the integrity of the data. However, it is possible that users may have to encounter with an error as soon as they type the command.
SQL Server Database Consistency Error: Causes
This command, namely DBCC CHECKDB determines the logical as well as the physical consistency of rows, index, relationships, allocation, etc. If any of these mentioned checks fail consistency error will be reported.
The reason of the failure of this checks is not one, but many. Some of the reasons are mentioned below:
Corruption of system fileCorrupted pages in memorySome problem with the Engine of SQL ServerIssue in any DriverSome issue in hardware system
Consistency Error in Database: Resolution
These are the following possible resolutions to resolve this error:
You can restore the database from a good backup. This is considered to be the best resolution to fix this error issue.Next thing you can do if you cannot restore from a backup is that you can check the features provided by CHECKDB to repair the errors.If there is a problem related to the file of the system or hardware, it is recommended to correct these things before restoring.
When you run DBCC CHECKDB Command a recommendation is given that shows the minimum repair option to repair all the errors. This is how the message looks like:
CHECKDB found 0 allocation errors and 18 consistency errors in database 'DatabaseName'.
repair_allow_data_loss is the minimum repair level for the errors found by DBCC CHECKDB (DatabaseName)
To remove and resolve all errors from CHECKDB, the repair recommendation is the minimum level of repair. It is not necessary that this option of repair can repair all the errors. This is also a fact that all the errors require different level of repair to resolve the error. This indicates that it is not mandatory that errors reported by CHECKDB, when repair_allow_data_loss is recommended, will result in the loss of data.
Repair is needed to know that whether the resolution of an error will result in the loss of the data. One of the best techniques to determine the level of repair for each table is to use DBCC CHECKTABLE for any, which reports an error. This will provide the details that what is the minimum level of repair for a given table.
This is how users can find the cause of consistency error:
You can check the Windows System Event Log for any system level, disk or driver related errorsWith the help of CHKDSK Command you check the file systemRun the diagnostics, if any, given by your hardware manufacturers for the computerWork with your hardware vendor or device manufacturer to ensure the drivers and other software components in I/O path are updated
Database errors may become a point of concerns for all the users of SQL Server. As we have discussed, in the above section SQL Server database consistency error can create a hurdle in between the work. We have also, learned some resolution to solve this issue. Apart from these resolutions, users can go for a third party utility, namely SQL MDF file recovery software
. This utility can be used if the problem cannot be resolved by the above mentioned methods.