What is DBCC?
The Database Consistency Checker Commands (DBCC) is used to check the logical and physical consistency of the database structure.The DBCC statements can fix and detect the problems.They are grouped into 4 categories as shown below :-
1)The Maintenance commands such as DBCC DBREPAR, DBCC DBREINDEX etc , they are mostly used for the maintenance tasks in SQL SERVER.
2)The Miscellaneous commands such as DBCC TRACEO, DBCC ROWLOCK etc , they are mostly used for enabling the row-level locking or removing DLL from the memory.
3)he Status Commands such as the DBCC SHOWCONTIG , DBCC OPENTRAN etc , they are mostly used for checking the status of the database.
4)The Validation Commands such as DBCC CHECKCATALOG, DBCC CHECKALLOCetc , they perform validation operations on the database.
The sample screen is shown below in which the DBCC SHOWCONTIG command is run.The DBCC SHOWCONTIG is used to display the fragmentation information for the data and indexes of the specified table.In the sample screen the "Customer" table is checked for the fragmentation information. If you see at the figure the "Scan density" is 100 if everything is ucontigious in this image it is 95.36% that is a decent percentage. So such type of useful information can be collected by the DBCC command and database performance and the maintenance can be improved.
Figure :-DBCC SHOWCONTIG command in action.