SQL XML Parsing Query for Element Hierarchy - sql

Question

I am attempting to write a SQL Query that will take in an XML object of undefined schema (YAY!) and transform it to a two column table of ElementName, Value columns. I was able to get a simple query down after some time (I am not a SQL person by any means).
DECLARE #strXml XML
SET #strXml = '<xml>
<FirstName>TEST</FirstName>
<LastName>PERSON</LastName>
<DOB>1/1/2000</DOB>
<TestObject>
<SomeProperty>CHECKED</SomeProperty>
<EmbeddedObject>
<SomeOtherProperty>NOT CHECKED</SomeOtherProperty>
</EmbeddedObject>
</TestObject>
</xml>'
DECLARE #XmlMappings TABLE
(
NodeName VARCHAR(64),
Value VARCHAR(128)
)
INSERT INTO #XmlMappings
SELECT doc.col.value('fn:local-name(.)[1]', 'varchar(64)') AS ElementName,
doc.col.value('.', 'varchar(128)') AS Value
FROM #strXml.nodes('/xml/*') doc(Col)
SELECT * FROM #XmlMappings
This query can handle the simple condition of the specified XML with only the first level elements. However elements such as TestObject and EmbeddedObject end up flattened. What I am looking for is to get some type of mapping like
ElementName | Value
=====================================================
FirstName | TEST
LastName | PERSON
DOB | 1/1/2000
TestObject.SomeProperty | CHECKED
TestObject.EmbeddedObject.SomeOtherProperty | NOT CHECKED
The hard part for me is the hierarchical structure with the . operator. I don't care if it is some other delimiter than . that gets output, it is more of just getting the output done, and I don't know enough about XML in SQL to be able to know even what to query.
Please note that I can also not use OPENXML since this is looking to be deployed on SQL Azure which does not support that feature at this time.

Answer 1

With a CTE and cross apply
;with cte as
(
select
convert(varchar(100), x.n.value('fn:local-name(.)','varchar(100)') ) as path,
convert(varchar(100), x.n.value('fn:local-name(.)','varchar(100)') ) AS name,
x.n.query('*') AS children,
x.n.value('.','varchar(1000)') as value
from #strxml.nodes('/xml/*') AS x(n)
union all
select
convert(varchar(100), x.path + '.' + c.n.value('fn:local-name(.)','varchar(100)') ),
convert(varchar(100), c.n.value('fn:local-name(.)','varchar(100)') ) ,
c.n.query('*'),
c.n.value('.','varchar(1000)')
from cte x
cross apply x.children.nodes('*') AS c(n)
)
select path, value from cte where datalength(children) = 5