数据库ntext,text字段的内容批量替换储存过程.

--select * from dbo.cms_detail


if exists(select 1 from tempdb.dbo.sysobjects where name like '#cms_detailtmp%')


DROP TABLE #cms_detailtmp


CREATE TABLE #cms_detailtmp




(




ID INT IDENTITY(1,1) PRIMARY KEY,




A TEXT




)






set nocount on


DECLARE @sTableName SYSNAME




DECLARE @sFieLd SYSNAME




DECLARE @sSrc VARCHAR(20)




DECLARE @sDest VARCHAR(20)






SET @sTableName = 'cms_detail' -- 待更新的表的名称




SET @sField = 'content' -- 待更新的字段的名称




SET @sSrc = '.MEGAJOY.COM' -- 要被替换的字符串（源字符串）




SET @sDest = '.JOY.CN' -- 进行替换的目标字符串








DECLARE @PTRVAL BINARY(16) -- 指向当前文本字段的指针




DECLARE @VAL VARCHAR(8000) -- 当前读取的文本字段的部分




DECLARE @PREVVAL VARCHAR(8000) -- 由于源字符串跨界产生的源字符串前缀回退部分




DECLARE @VALLEN INT -- 当前读取的文本字段的长度




DECLARE @STATEMENT NVARCHAR(512) -- 进行执行sp_executesql的SQL语句部分




DECLARE @ISNTEXT BIT -- 是否NTEXT字段类型0: TEXT 1: NTEXT




DECLARE @READPTR INT -- 当前TEXT或者NTEXT字段已经读取或者处理的字符偏移量




DECLARE @READLEN INT -- 当次TEXT或者NTEXT字段读取的长度




DECLARE @SRCLEN INT -- 源字符串的长度




DECLARE @DESTLEN INT -- 目标字符串的长度




DECLARE @VALBINARY VARBINARY(8000) -- 本次读取的文本字段的BINARY表示，用来识别是否已经截断了一个DBCS字符




DECLARE @VALBINARYLEN INT -- 本次读取的文本字段的BINARY表示的长度




DECLARE @HALFDBCS INT -- 当前识别的是否DBCS的一部分












SET @SRCLEN = LEN( @sSrc )




SET @DESTLEN = LEN( @sDest )








DECLARE csrTextUpdate CURSOR LOCAL FOR




SELECT TEXTPTR(content),




DATALENGTH(content)




FROM cms_detail




FOR UPDATE OF content








OPEN csrTextUpdate




declare @count int


select @count=count(*) from cms_detail


print '共'+cast(@count as varchar);


set @count =1;






-- xtype = 35 为TEXT xtype = 99 为NTEXT




IF EXISTS( SELECT * FROM SYSCOLUMNS WHERE ID = OBJECT_ID('cms_detail') AND NAME = @sField AND XTYPE = 35 )




SET @ISNTEXT = 0




ELSE




SET @ISNTEXT = 1








FETCH csrTextUpdate INTO @PTRVAL, @VALLEN




WHILE @@FETCH_STATUS = 0




BEGIN


print '现在是第'+cast(@count as varchar);


set @count=@count+1;


IF @VALLEN > 8000




BEGIN








SET @VALLEN = CASE WHEN @ISNTEXT = 1 THEN @VALLEN / 2 ELSE @VALLEN END




SET @READPTR = 0




SET @READLEN = CASE WHEN @VALLEN > @READPTR + 2000 THEN 2000 ELSE @VALLEN - @READPTR END








TRUNCATE TABLE #cms_detailtmp








-- 分拆TEXT字段到#cms_detailtmp表




WHILE @READPTR < @VALLEN




BEGIN








SET @READLEN = CASE WHEN @VALLEN > @READPTR + 2000 THEN 2000 ELSE @VALLEN - @READPTR END




SET @STATEMENT = N'READTEXT cms_detail.content @PTRVAL '




+ CONVERT( NVARCHAR, @READPTR ) + ' '




+ CONVERT( NVARCHAR, @READLEN )








SET @READPTR = @READPTR + @READLEN








INSERT INTO #cms_detailtmp




EXEC sp_executesql @STATEMENT,




N'@PTRVAL BINARY(16)',




@PTRVAL






-- 判断最后一个字符是否为中文字符，如果是，则需要进行回退操作








IF @@ROWCOUNT = 1 AND @ISNTEXT = 0




BEGIN




SELECT @VALBINARY = CONVERT( VARBINARY(8000), CONVERT( VARCHAR(8000), A ))




FROM #cms_detailtmp WHERE ID = @@IDENTITY




SET @VALBINARYLEN = DATALENGTH(@VALBINARY)








IF @VALBINARYLEN = @READLEN




BEGIN




SET @HALFDBCS = 0




END




ELSE




BEGIN




SET @HALFDBCS = 1




END








IF @HALFDBCS = 1




BEGIN




-- 回退一个字符串




UPDATE #cms_detailtmp




SET A = CONVERT( VARCHAR(8000), SUBSTRING( @VALBINARY, 1, @READLEN - 1 ) )




WHERE ID = @@IDENTITY




SET @READPTR = @READPTR - 1




END




END




END








-- 进行分批替换,如果有需要被替换的字符串跨段的情况需要进行跨段处理




DECLARE csrTmp CURSOR LOCAL FOR




SELECT A FROM #cms_detailtmp




FOR UPDATE OF A




OPEN csrTmp




FETCH csrTmp INTO @VAL








SET @PREVVAL = ''




WHILE @@FETCH_STATUS = 0




BEGIN




SET @VAL = REPLACE( @PREVVAL + @VAL, @sSrc, @sDest )








SET @VALLEN = LEN(@VAL)








SET @READPTR = CASE WHEN @SRCLEN > @VALLEN THEN @VALLEN ELSE @SRCLEN END








SET @PREVVAL = ''








WHILE @READPTR > 0




BEGIN








IF RIGHT( @VAL, @READPTR ) = LEFT( @sSrc, @READPTR )




BEGIN








-- 找到前缀，将当前的@VAL截断一部分




UPDATE #cms_detailtmp




SET [A] = LEFT( @VAL, @VALLEN - @READPTR )




WHERE CURRENT OF csrTmp








SET @PREVVAL = RIGHT( @VAL, @READPTR )




BREAK




END








SET @READPTR = @READPTR - 1




END








IF @PREVVAL = ''




BEGIN




UPDATE #cms_detailtmp




SET [A] = @VAL




WHERE CURRENT OF csrTmp




END








FETCH csrTmp INTO @VAL




END




DEALLOCATE csrTmp












-- 更新TEXT字段




UPDATETEXT cms_detail.content @PTRVAL 0 NULL ''








DECLARE csrUpdateText CURSOR LOCAL FOR




SELECT A FROM #cms_detailtmp








OPEN csrUpdateText




FETCH csrUpdateText INTO @VAL




WHILE @@FETCH_STATUS = 0




BEGIN








UPDATETEXT cms_detail.content @PTRVAL NULL 0 @VAL




FETCH csrUpdateText INTO @VAL




END




DEALLOCATE csrUpdateText








END




ELSE




BEGIN




-- 如果是NTEXT的类型，字符串的长度为字节长度的/2




UPDATE cms_detail




SET content = REPLACE( CONVERT( VARCHAR(8000), content), @sSrc, @sDest )




WHERE CURRENT OF csrTextUpdate




END








FETCH csrTextUpdate INTO @PTRVAL, @VALLEN




END








DEALLOCATE csrTextUpdate




GO