Repair a corrupted SQL database such as a power outage _mssql

such as the database name: Freehost
The first is to set it to Single-user mode, then fix it, and finally restore multiuser mode.
ALTER DATABASE [Freehost] SET Single_user
Go
DBCC CHECKDB (' Freehost ', repair_allow_data_loss) with TABLOCK
Go
ALTER DATABASE [Freehost] SET Multi_user
Go


--CHECKDB has 3 parameters:
--repair_allow_data_loss
--Perform all repairs performed by repair_rebuild, including assigning and unassign rows and pages to correct assignment errors, structural rows or pages, and deleting corrupted text objects. These fixes can cause some data loss. A repair operation can be completed under a user transaction to allow the user to roll back the changes. If you roll back the repair, the database will still contain errors and should be recovered from the backup. If an incorrect fix is omitted due to the level of repair provided, any fixes that depend on the repair will be omitted. After the repair is complete, back up the database.
--repair_fast for small, time-consuming fixes, such as fixing additional keys in a nonclustered index. These fixes can be done quickly, and there is no risk of losing data.
--repair_rebuild performs all the repairs performed by Repair_fast, including the need for a longer period of repair, such as rebuilding an index. There is no risk of losing data when performing these repairs.

--DBCC CHECKDB (' Freehost ') with No_infomsgs,physical_only