How to get specific XML namespace in XQuery in SQL Server - sql

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.