最近因为公司域名www.megajoy.com要换成www.joy.cn (这里我为公司做一个广告，哈哈)
所以我写了两个存储过程，实现了一次性替换数据库中所有表所有列的关键字，包括了数据表中的所有文本字段(varchar.nvarchar,ntext,text等)..
当然要实现类型为varchar,nvarchar的字段是很容易实现的，用一句SQL就可以搞定：
update Table set Column=Replace(Column,'oldkeyword','newkeyword').
但如果你用这句SQL语句去更新类型为text,ntext的字段是就要报错了：
err info:消息 8116，级别 16，状态 1，第 1 行
参数数据类型 text 对于 replace 函数的参数 1 无效。
这里也许有人会想到，可以先把text,ntext类型转换成varchar,nvarchar来实现，SQL语句如下：
update Table set Column=Replace(Cast(Column as varchar(8000)),'oldkeyword','newkeyword')
但是，你想过没有，如果ntext,text类型的列里，已存放的数据大于8000字节的话，你的数据就会被丢失了。所有，你要慎用！！
不过还好，MS提供了updatetext(使用 UPDATETEXT 可以只更改 text、ntext 或 image 列的一部分).
如果你要查看updatetext的用法，请查看SQL联机帮助丛书.
费话不多说了，下面我简单的介绍一下我的解决方案以及实现的关键技术.
1:sp_msforeachtable 用来loop表中的所有列
2:更新类型为ntext,text类型的列时，先判断DATALENGTH(Column)是否大于8000字节，如果小于8000字节的话，我们可以使用
update Table set Column=Replace(Cast(Column as varchar(8000)),'oldkeyword','newkeyword')来更新。
源码如下：
UpdateTextColumn
1
Create proc [dbo].[UpdateTextColumn]
2@Table varchar(100),
3@Columns varchar(200),
4@old varchar(100),
5@new varchar(100)
6as
7 set nocount on
8 declare @sql nvarchar(2000)
9 declare @Column varchar(50)
10 declare @cpos int,@npos int
11 declare @curoffset int
12 set @cpos=1;
13 set @npos=1;
14 set @npos=charindex(',',@Columns,@cpos);
15 set @curoffset=0;
16
17 while(@npos>0)
18 begin
19 set @Column = substring(@Columns,@cpos,@npos-@cpos);
20 set @cpos = @npos+1
21 set @npos=charindex(',',@Columns,@cpos);
22
23 set @sql = 'update '+@Table+' set '+@Column+'=replace(cast('+@Column+' as varchar(8000)),@old,@new) where Datalength('+@Column+')<=8000';
24 EXECUTE sp_executesql @Sql,
25 N'@old varchar(100),@new varchar(100)',
26 @old,
27 @new
28 declare @ptr binary(16) ,@offset int,@dellen int
29
30 set @dellen = len(@old)
31
32 set @offset = 1
33 while @offset>=1
34 begin
35 if @curoffset<>0
36 set @curoffset=@offset;
37 set @offset = 0
38 set @sql = 'select top 1 @offset = PATINDEX(''%'+@old+'%'' , '+@Column+'), @ptr = textptr('+@Column+') from '+@Table+' where Datalength('+@Column+')>8000 and '+@Column+' like ''%'+@old+'%''';
39 EXEC sp_executesql @Sql,N'@offset int OUTPUT,@ptr binary(16) OUTPUT,@old varchar(100),@curoffset int',
40 @offset OUTPUT,@ptr OUTPUT,@old,@curoffset;
41
42 if (@offset is not null) and (@offset > 0)
43 begin
44 set @offset = @offset-1
45
46 set @sql='updatetext '+@Table+'.'+@Column+' @ptr @offset @dellen @new';
47 EXEC sp_executesql @Sql,N'@offset int ,@ptr binary(16),@dellen int,@new varchar(100)',@offset,@ptr,@dellen,@new;
48 end
49 end
50end
Create proc [dbo].[UpdateTextColumn]
@Table varchar(100),
@Columns varchar(200),--eg:Column1,Column2,
@old varchar(100),
@new varchar(100)
as
set nocount on
declare @sql nvarchar(2000)
declare @Column varchar(50)
declare @cpos int,@npos int
set @cpos=1;
set @npos=1;
set @npos=charindex(',',@Columns,@cpos);
while(@npos>0)
begin
set @Column = substring(@Columns,@cpos,@npos-@cpos);
set @cpos = @npos+1
set @npos=charindex(',',@Columns,@cpos);
set @sql = 'update '+@Table+' set '+@Column+'=replace(cast('+@Column+' as varchar(8000)),@old,@new) where Datalength('+@Column+')<=8000';
EXECUTE sp_executesql @Sql,
N'@old varchar(100),@new varchar(100)',
@old,
@new
declare @ptr binary(16) ,@offset int,@dellen int
set @dellen = len(@old)
set @offset = 1
while @offset>=1
begin
set @offset = 0
set @sql = 'select top 1 @offset = charindex('''+@old+''' , '+@Column+'), @ptr = textptr('+@Column+') from '+@Table+' where Datalength('+@Column+')>8000 and '+@Column+' like ''%'+@old+'%''';
EXEC sp_executesql @Sql,N'@offset int OUTPUT,@ptr binary(16) OUTPUT,@old varchar(100)',
@offset OUTPUT,@ptr OUTPUT,@old;
if @offset > 0
begin
set @offset = @offset-1
set @sql='updatetext '+@Table+'.'+@Column+' @ptr @offset @dellen @new';
EXEC sp_executesql @Sql,N'@offset int ,@ptr binary(16),@dellen int,@new varchar(100)',@offset,@ptr,@dellen,@new;
end
end
end
go
ReplaceKeyWord
Create proc [dbo].[ReplaceKeyWord]
@old nvarchar(100),
@new nvarchar(100)
as
declare @sql nvarchar(1000)
set @sql=N'
declare @s nvarchar(4000),@tbname sysname
select @s=N'''',@tbname=N''?''
select @s=@s+N'',''+quotename(a.name)+N''=replace(''+quotename(a.name)+N'',N'''''+@old+''''',N'''''+@new+''''')''
from syscolumns a,systypes b
where a.id=object_id(@tbname)
and a.xusertype=b.xusertype
and b.name like N''%char''
if @@rowcount>0
begin
set @s=stuff(@s,1,1,N'''')
exec(N''update ''+@tbname+'' set ''+@s)
end '
--print @sql
exec sp_msforeachtable @sql;
set @sql=N'
declare @s nvarchar(4000),@tbname sysname
select @s=N'''',@tbname=N''?''
select @s=@s+quotename(a.name)+N'',''
from syscolumns a,systypes b
where a.id=object_id(@tbname)
and a.xusertype=b.xusertype
and b.name like N''%text''
if @@rowcount>0
begin
exec UpdateTextColumn @tbname,@s,'''+@old+''','''+@new+'''
end
' ;
exec sp_msforeachtable @sql
go
使用方法如下：Exec ReplaceKeyWord 'www.megajoy.com','www.joy.cn'
以上是全部源代码，如果您发现了错误，欢迎指出，我会在第一时间修改。如果您有更好的解决方案，也欢迎共享，谢谢！！
补充：
如果是mssql2005版本,您只需要如下代码：
MSSQL2005
1declare @sql nvarchar(1000)
2declare @old nvarchar(100)
3declare @new nvarchar(100)
4set @old ='megagggjoy.com'
5set @new ='joy.cn'
6set @sql=N'
7declare @s nvarchar(4000),@tbname sysname
8select @s=N'''',@tbname=N''?''
9select @s=@s+N'',''+quotename(a.name)+N''=replace(''+quotename(a.name)+N'',N'''''+@old+''''',N'''''+@new+''''')''
10from syscolumns a,systypes b
11where a.id=object_id(@tbname)
12and a.xusertype=b.xusertype
13and b.name like N''%char''
14if @@rowcount>0
15begin
16set @s=stuff(@s,1,1,N'''')
17exec(N''update ''+@tbname+'' set ''+@s)
18end '
19--print @sql
20exec sp_msforeachtable @sql;
21
22set @sql=N'
23declare @s nvarchar(4000),@tbname sysname
24select @s=N'''',@tbname=N''?''
25select @s=@s+N'',''+quotename(a.name)+N''=replace(cast(''+quotename(a.name) +N''as varchar(max)),N'''''+@old+''''',N'''''+@new+''''')''
26from syscolumns a,systypes b
27where a.id=object_id(@tbname)
28and a.xusertype=b.xusertype
29and b.name like N''%text''
30print @s
31if @@rowcount>0
32begin
33set @s=stuff(@s,1,1,N'''')
34exec(N''update ''+@tbname+'' set ''+@s)
35end '
36exec sp_msforeachtable @sql
declare @sql nvarchar(1000)
declare @old nvarchar(100)
declare @new nvarchar(100)
set @old ='megagggjoy.com'
set @new ='joy.cn'
set @sql=N'
declare @s nvarchar(4000),@tbname sysname
select @s=N'''',@tbname=N''?''
select @s=@s+N'',''+quotename(a.name)+N''=replace(''+quotename(a.name)+N'',N'''''+@old+''''',N'''''+@new+''''')''
from syscolumns a,systypes b
where a.id=object_id(@tbname)
and a.xusertype=b.xusertype
and b.name like N''%char''
if @@rowcount>0
begin
set @s=stuff(@s,1,1,N'''')
exec(N''update ''+@tbname+'' set ''+@s)
end '
--print @sql
exec sp_msforeachtable @sql;
set @sql=N'
declare @s nvarchar(4000),@tbname sysname
select @s=N'''',@tbname=N''?''
select @s=@s+N'',''+quotename(a.name)+N''=replace(cast(''+quotename(a.name) +N''as varchar(max)),N'''''+@old+''''',N'''''+@new+''''')''
from syscolumns a,systypes b
where a.id=object_id(@tbname)
and a.xusertype=b.xusertype
and b.name like N''%text''
print @s
if @@rowcount>0
begin
set @s=stuff(@s,1,1,N'''')
exec(N''update ''+@tbname+'' set ''+@s)
end '
exec sp_msforeachtable @sql
