1 Backup Log DNName WITH no_log
2 GO
3 DUMP TRANSACTION DNName WITH no_log
4 GO
5 USE DNName 
6 DBCC SHRINKFILE (2)
7 GO

 1 USE [master]
 2 GO
 3 ALTER DATABASE DNName SET RECOVERY SIMPLE WITH NO_WAIT
 4 GO
 5 ALTER DATABASE DNName SET RECOVERY SIMPLE   --简单模式
 6 GO
 7 USE DNName 
 8 GO
 9 DBCC SHRINKFILE (N‘DNName_Log‘ , 11, TRUNCATEONLY)
10 GO
11 USE [master]
12 GO
13 ALTER DATABASE DNName SET RECOVERY FULL WITH NO_WAIT
14 GO
15 ALTER DATABASE DNName SET RECOVERY FULL  --还原为完全模式
16 GO