DUMP TRANSACTION LOG on SQL Server

dump transaction test with no_log
DBCC SHRINKFILE(PSIWeb_log, 20)
BACKUP LOG PSIWeb WITH TRUNCATE_ONLY
DBCC SHRINKFILE(PSIWeb_log, 1)
GO
exec sp_detach_db 'PSIWeb', 'true'
exec sp_attach_single_file_db @dbname = 'PSIWeb',
@physname = 'C:\MSSQL7\Data\PSIWeb_Data.MDF'