SQL Server 数据库操作实用技巧锦集(2)

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


USE databasename -- 要操作的数据库名
SELECT @LogicalFileName = 
'databasename_log', -- 日志文件名
@MaxMinutes = 10, 
-- Limit on time allowed to wrap log.
@NewSize = 1 -- 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