dbcc checkdb runs the same checks as dbcc checktable on each table in the specified database.
If you do not specify a database name, dbcc checkdb checks the current database. dbcc checkdb produces messages similar to those returned by dbcc checktable, and makes the same types of corrections.
If you specify the optional skip_ncindex, dbcc checkdb does not check any of the nonclustered indexes on user tables in the database.
If the database extends over a series of partitions, dbcc checkdb performs its checks on each partition.