Can someone explain how OpenXML works(in this SP)? - stored-procedures

Question

I am looking at this tutorial
and it confuses me as I don't get the SP
CREATE PROCEDURE [dbo].[spTEST_InsertXMLTEST_TEST](#UpdatedProdData nText)
AS
DECLARE #hDoc int
exec sp_xml_preparedocument #hDoc OUTPUT,#UpdatedProdData
INSERT INTO TBL_TEST_TEST(NAME)
SELECT XMLProdTable.NAME
FROM OPENXML(#hDoc, 'ArrayOfTBL_TEST_TEST/TBL_TEST_TEST', 2)
WITH (
ID Int,
NAME varchar(100)
) XMLProdTable
EXEC sp_xml_removedocument #hDoc
First I am using SQL 2005 and do I need to install something on the server to get OPENXML to work? Next I don't get what these statements do
// not sure what #hDoc is for and why it is an int
DECLARE #hDoc int
// don't get what this is and where the output is.
exec sp_xml_preparedocument #hDoc OUTPUT,#UpdatedProdData
// don't get why it is "XMLProdTable" and if it always has to be like this
SELECT XMLProdTable.NAME
// pretty muct don't get anything what is happening after OPENXML
FROM OPENXML(#hDoc, 'ArrayOfTBL_TEST_TEST/TBL_TEST_TEST', 2)
WITH (
ID Int,
NAME varchar(100)
) XMLProdTable
// Don't know what this is really executing
EXEC sp_xml_removedocument #hDoc
Thanks

Answer 1

// not sure what #hDoc is for and why
it is an int DECLARE #hDoc int
That will be used in the next call, it is an output parameter
// don't get what this is and where
the output is. exec
sp_xml_preparedocument #hDoc
OUTPUT,#UpdatedProdData
It is calling the sp_xml_preparedocument, output just means it is an output parameter, #hDoc will be populated with the value in the proc
// don't get why it is "XMLProdTable"
and if it always has to be like this
SELECT XMLProdTable.NAME
XMLProdTable is the alias used in the next part, the CTE is named XMLProdTable
// pretty muct don't get anything what
is happening after OPENXML FROM
OPENXML(#hDoc,
'ArrayOfTBL_TEST_TEST/TBL_TEST_TEST',
2)
WITH (
ID Int,
NAME varchar(100)
) XMLProdTable --alias
It populates the CTE with values from the XML document under the ArrayOfTBL_TEST_TEST/TBL_TEST_TEST tag
// Don't know what this is really
executing EXEC sp_xml_removedocument
#hDoc
This is releasing the document from memory
Take a look at the samples here http://msdn.microsoft.com/en-us/library/ms186918.aspx