一般情况下，当SQL数据库日记文件太大时，很难将其压缩到更小。
通过下面的这段批处理SQL程序序就可以实现了。（试用通过！！！）
注：修改下面的三个备注处的参数即可COPY到查询分析器里执行了。

SET NOCOUNT ON
DECLARE @LogicalFileName sysname,
@MaxMinutes INT,
@NewSize INT

USE joekoe -- 要操作的数据库名
SELECT @LogicalFileName = \'joekoe_log\', -- 日志文件名
@MaxMinutes = 10, -- Limit on time allowed to wrap log.
@NewSize = 20 -- 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