Inserting an attribute in multiple XML Nodes using XML.modify() in SQL 2005

Question

I have an @XML document created from a single select statement.

<root>
 <node>
  <node1>
   <targetNode>
   </targetNode>
  </node1>
  <node1>
   <targetNode>
   </targetNode>
  </node1>
  <node1>
   <targetNode>
   </targetNode>
  </node1>
 </node>
 <node>
  ......
 </node>
</root>

I want to insert the xsi:nil as an attribute of 'targetNode' for this document.

@XML.modify( 'insert attribute xsi:nil {"true"} into (root/node/node1/targetNode) [1]') 

The above will insert the attribute into the first occurance of the targetNode in the @XML document. The insert statement however will only work on a single node. Is there any way I can insert this attribute into all instances of targetNode in the @XML document.

Answer 1

you can do this in the select, that you are using to create your xml, using the XSINILL parameter.

http://msdn.microsoft.com/en-us/library/ms178079.aspx

(here is a very rough example)

--create 2 tables and put some data in them
create table node
(
   id int identity(1,1) primary key,
   node int
)
GO
create table node1
(
   id int identity(1,1) primary key,
   nodeid int foreign key references node(id),
   targetnode int
)
GO

insert into node
select 1
GO 5

insert into node1
select 1,2
union 
select 2,null
union 
select 3,2
union 
select 4,null
--

--select statement to generate the xml
SELECT TOP(1)
   (SELECT
      (  SELECT targetnode
         FROM    node1
         WHERE   nodeid = node.id 
         FOR XML AUTO,
         ELEMENTS XSINIL,
         TYPE
      )
   FROM    node FOR XML AUTO,
   ELEMENTS,
   TYPE
   )
FROM   node FOR XML RAW('root'),
       ELEMENTS

Answer 2

I found a simple and elegant solution in DML operations on multiple nodes http://blogs.msdn.com/b/denisruc/archive/2005/09/19/471562.aspx

The idea is to count how many nodes and modify them one by one:

DECLARE @iCount int
SET @iCount = @var.value('count(root/node/node1/targetNode)','int')

DECLARE @i int
SET @i = 1

WHILE (@i <= @iCount)
BEGIN
   @xml.modify('insert attribute xsi:nil {"true"} into (root/node/node1/targetNode)[sql:variable("@i")][1]')
   SET @i = @i + 1
END

Answer 3

That's not possible with the modify-function. It only works on a single node.

You can manipulate it as string, although that is definitely ugly and possibly wrong in some cases, depending on the actual structure of your XML.

Like this:

declare @xml as xml
set @xml = '<root>
 <node>
  <node1>
   <targetNode>
   </targetNode>
  </node1>
  <node1>
   <targetNode>
   </targetNode>
  </node1>
  <node1>
   <targetNode>
   </targetNode>
  </node1>
 </node>
</root>
'

set @xml = replace(cast(@xml as nvarchar(max)), '<targetNode/>', '<targetNode xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true" />')
select @xml