SQL Server：XQUERY名称空间解析

Question

I have the following XML:

    declare @xml    xml = '
    <DiscoverResponse xmlns="urn:schemas-microsoft-com:xml-analysis">
      <return>
        <root xmlns="urn:schemas-microsoft-com:xml-analysis:rowset">
          <row>
            <xars:METADATA xmlns="http://schemas.microsoft.com/analysisservices/2003/engine">
              <Server>
                <Name>myName</Name>
              </Server>
            </xars:METADATA>
          </row>
        </root>
       </return>
    </DiscoverResponse>'

And I have been able to parse up to the <row> tag with the following query

    ; WITH XMLNAMESPACES(
        'urn:schemas-microsoft-com:xml-analysis'                        AS ns1,
        'urn:schemas-microsoft-com:xml-analysis:rowset'                 AS ns2
    )
    select 
        t.x.value('ns2:Name[1]','varchar(100)') AS Name
    from @xml.nodes('//ns1:DiscoverResponse/ns1:return/ns2:root/ns2:row') t(x)

I am stuck trying to figure out how to query past the <xars:METADATA> tag. That is, I have not been able successfully construct a namespace declaration and path specification to get to the <Server> node (I am trying to extract the Name of the Server). I am running afoul of the extra colon it seems.

Thanks in advance.

Answer 1

1) That XML isn't valid.

2) If you want to avoid XML NAMESPACES then you could use following syntax for every XML element: *:XmlElement .

Example:

declare @xml    xml = N'<DiscoverResponse xmlns="urn:schemas-microsoft-com:xml-analysis">
      <return>
        <root xmlns="urn:schemas-microsoft-com:xml-analysis:rowset">
          <row>
            <xars:METADATA xmlns="http://schemas.microsoft.com/analysisservices/2003/engine" xmlns:xars="aaa">
              <Server>
                <Name>myName</Name>
              </Server>
            </xars:METADATA>
          </row>
        </root>
       </return>
    </DiscoverResponse>'

SELECT  x.y.value('(*:Server/*:Name/text())[1]', 'NVARCHAR(260)') AS Server_Name
FROM    @xml.nodes('*:DiscoverResponse/*:return/*:root/*:row/*:METADATA') x(y)

Results:

Server_Name
-----------
myName

Answer 2

You have a couple of things going wrong:

1. The xars namespace is not declared in the xml. I believe the namespace for xars is "urn:schemas-microsoft-com:xml-analysis:rowset" which you actually have as a default namespace (form the root) but not explicitly mapped to the xars prefix.

2. The xquery is missing the reference to namespace " http://schemas.microsoft.com/analysisservices/2003/engine " which in the xml is set as the default namespace from and including METADATA.

So first, I've altered your sample xml to include a namespace for xars: I expect your actual xml has this declared elsewhere, so you problably dont need to make this change.

declare @xml    xml = N'<DiscoverResponse xmlns="urn:schemas-microsoft-com:xml-analysis">
  <return>
    <root xmlns="urn:schemas-microsoft-com:xml-analysis:rowset">
      <row>
        <xars:METADATA xmlns="http://schemas.microsoft.com/analysisservices/2003/engine" xmlns:xars="urn:schemas-microsoft-com:xml-analysis:rowset">
          <Server>
            <Name>myName</Name>
          </Server>
        </xars:METADATA>
      </row>
    </root>
   </return>
</DiscoverResponse>'

Second, I've added the ' http://schemas.microsoft.com/analysisservices/2003/engine ' (as ns3) to your query and change the query to reference it.

; WITH XMLNAMESPACES(
    'urn:schemas-microsoft-com:xml-analysis'                        AS ns1,
    'urn:schemas-microsoft-com:xml-analysis:rowset'                 AS ns2,
    'http://schemas.microsoft.com/analysisservices/2003/engine'     AS ns3
)
select 
    t.x.value('ns3:Name[1]','varchar(100)') AS Name
from @xml.nodes('//ns1:DiscoverResponse/ns1:return/ns2:root/ns2:row/ns2:METADATA/ns3:Server') t(x)