DBCC (Database Console Commands) statements deal with four type of operations:
Maintenance. Maintenance tasks on a database, index, or filegroup.
Miscellaneous. Miscellaneous tasks such as enabling trace flags or removing a DLL from memory.
Informational. Tasks that gather and display various types of information.
Validation. Validation operations on a database, table, index, catalog, filegroup, or allocation of database pages.
DBCC CHECKDB - Checks the logical and physical integrity of all the objects in the specified database. It's include the execution of DBCC CHECKALLOC, DBCC CHECKTABLE, and DBCC CHECKCATALOG commands. You can repair the found errors by three ways.
REPAIR_ALLOW_DATA_LOSS option Tries to repair all reported errors. These repairs can cause some data loss.
REPAIR_FAST Maintains syntax for backward compatibility only. No repair actions are performed.
REPAIR_REBUILD Performs repairs that have no possibility of data loss. This can include quick repairs, such as repairing missing rows in non-clustered indexes, and more time-consuming repairs, such as rebuilding an index.
The sys.dm_exec_requests catalog view contains information about the progress and the current phase of execution of the DBCC CHECKDB, CHECKFILEGROUP, and CHECKTABLE commands. The percent_complete column indicates the percentage complete of the command, and the command column reports the current phase of the execution of the command.