如何在SQL Server的XQuery中获取特定的XML名称空间

Question

I have a XML that I need one specific namespace according to node like temprature with hls i need namespace of that " http://www.schema.hls.com/extension " I have tried with these

DECLARE @EventXML AS XML

SET @EventXML='<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ns:test xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:ns="urn:global:test:xsd:1" 
xmlns:hls="http://schema.hls.com/extension" creationDate="2007-01-25T00:00:00Z"
schemaVersion="1.0">
<TestBody>
<TestList>
<TestEvent>
    <hls:temperature>20</hls:temperature>
  </TestEvent>
</TestList>
</TestBody>
</ns:test>'

SELECT 
OE.value('@ns','varchar(50)') + '#' + OE.value('fn:local-name(.)[1]','varchar(50)'),
OE.value('@id','varchar(50)'),
CONVERT(VARCHAR(4000),CASE WHEN OE.exist('./*') =1 THEN OE.query('./*')  ELSE    
OE.value('./text()[1]','varchar(100)') END)
FROM @EventXML.nodes('//TestEvent/*') TestEvent(OE)
WHERE OE.value('fn:local-name(.)[1]','varchar(50)') IN --(@tag) 
(SELECT  Split.a.value('.', 'VARCHAR(100)') AS extag 
FROM  (SELECT   CONVERT(XML,'<M>' + REPLACE(ISNULL('temperature','0'), ',', '</M><M>') + '</M>') AS String 
 ) AS A CROSS APPLY String.nodes ('/M') AS Split(a))  

I am using these in SQL query window but getting only third column value 20 not get namespace by @ns

Please suggest how to get the namespace

OE.value('@ns','varchar(50)') 

by these.

thanks in advanced.

Answer 1

Your code and XML somehow just don't quite match up - and the query is really quite confusing....

If you want to fetch the data, you must respect the XML namespaces in play. You need to declare them with a WITH XMLNAMESPACES() construct, and you need to use them in your XPath.

But also: the node you're selecting ( <hls:temperature> ) doesn't really have any id and ns attributes..... so of course you're not getting any values!

I tried to use a trimmed down version and I added the two attributes - just to show how to use the XML namespaces stuff in your code.

Here it comes:

DECLARE @EventXML AS XML

SET @EventXML = 
   '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <ns:test xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xmlns:ns="urn:global:test:xsd:1" 
             xmlns:hls="http://schema.hls.com/extension" 
             creationDate="2007-01-25T00:00:00Z" schemaVersion="1.0">
       <TestBody>
          <TestList>
             <TestEvent>
                <hls:temperature ns="test" id="42">20</hls:temperature>
             </TestEvent>
         </TestList>
      </TestBody>
   </ns:test>'

-- define your XML namespaces that are in play. 
-- You *MUST* match the namespace definition, but the *prefixes* that you define
-- can be something else entirely than in the XML document!
-- Of course, inside your XPath, you *MUST* use the defined prefixes!
;WITH XMLNAMESPACES('urn:global:test:xsd:1' AS x1, 
                    'http://schema.hls.com/extension' AS x2)
SELECT 
    OE.value('@ns', 'varchar(50)'),
    OE.value('@id', 'varchar(50)')
FROM 
    @EventXML.nodes('/x1:test/TestBody/TestList/TestEvent/x2:*') TestEvent(OE)

This code - using the XML namespaces defined and used in your XML - produces this output:

(No column name)  (No column name)
test                   42

So this shows how you can access the attributes - if they are present! - on your XML nodes, even with the presence of XML namespaces.