sql server 清理日志存储过程

代码
ALTER PROC [dbo].[CleanTranLog]
AS 
    BEGIN
        DECLARE @num TINYINT --执行次数
        DECLARE @backLogName VARCHAR(100) ;--备份日志文件名称
        DECLARE @backLogPath VARCHAR(100) ; --备份日志文件的路径
        SET @num = 0 ;
        SET @backLogPath = N'C:\SQLBackup' ;--设定备份日志的路径
        --备份3次镜像日志文件，同时删除
        WHILE( @num < 3 )
            BEGIN
                DECLARE @LogPath VARCHAR(100)
                SET @backLogName = CAST(@num as VARCHAR(2)) + '.trn' ;
                SET @LogPath = @backLogPath + '\' + @backLogName
                BACKUP LOG Mirror TO DISK = @LogPath WITH NOFORMAT, NOINIT,
                    NAME= @backLogName, SKIP, REWIND, NOUNLOAD,STATS = 10
                SET @num = @num + 1 
                --删除刚备份的trn日志文件结束的备份日志文件
                EXECUTE master.dbo.xp_delete_file 0, @LogPath ;
            end
         --收缩日志文件到200M
        DBCC SHRINKFILE (mirror_Log, 2) ;     
    END