-----
            SET NOCOUNT ON
            DECLARE @LogicalFileName sysname,
            @MaxMinutes INT,
            @NewSize INT
            USE     Marias
            -- 要操作的数据库名
            SELECT  @LogicalFileName = 'Marias_log'
            -- 日志文件名
            @MaxMinutes = 10,
            -- Limit on time allowed to wrap log.
            @NewSize = 100
            -- 你想设定的日志文件的大小(M)
            -- Setup / initialize
            DECLARE @OriginalSize int
            SELECT @OriginalSize = size
            FROM sysfiles
            WHERE name = @LogicalFileName
            SELECT 'Original Size of ' + db_name() + ' LOG is ' +
            CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' +
            CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB'
            FROM sysfiles
            WHERE name = @LogicalFileName
            CREATE TABLE DummyTrans
            (DummyColumn char (8000) not null)
            DECLARE @Counter   INT,
            @StartTime DATETIME,
            @TruncLog  VARCHAR(255)
            SELECT  @StartTime = GETDATE(),
            @TruncLog = 'BACKUP LOG '
            + db_name() + ' WITH TRUNCATE_ONLY'
            DBCC SHRINKFILE (@LogicalFileName, @NewSize)
            EXEC (@TruncLog)
            -- Wrap the log if necessary.
            WHILE     @MaxMinutes > DATEDIFF
            (mi, @StartTime, GETDATE()) -- time has not expired
            AND @OriginalSize = (SELECT size
            FROM sysfiles WHERE name = @LogicalFileName)
            AND (@OriginalSize * 8 /1024) > @NewSize
            BEGIN -- Outer loop.
            SELECT @Counter = 0
            WHILE  ((@Counter < @OriginalSize / 16)
            AND (@Counter < 50000))
            BEGIN -- update
            INSERT DummyTrans VALUES ('Fill Log')
            DELETE DummyTrans
            SELECT @Counter = @Counter + 1
            END
            EXEC (@TruncLog)
            END
            SELECT 'Final Size of ' + db_name() + ' LOG is ' +
            CONVERT(VARCHAR(30),size) + ' 8K pages or ' +
            CONVERT(VARCHAR(30),(size*8/1024)) + 'MB'
            FROM sysfiles
            WHERE name = @LogicalFileName
            DROP TABLE DummyTrans
            SET NOCOUNT OFF