OPENXML, a Transact-SQL keyword, provides a rowset over in-
memory XML documents that is similar to a table or a view. 
OPENXML allows access to XML data as though it is a 
relational rowset. It does this by providing a rowset view 
of the internal representation of an XML document. The 
records in the rowset can be stored in database tables. 

OPENXML can be used in SELECT and SELECT INTO statements 
wherever rowset providers, a view, or OPENROWSET can appear 
as the source. For information about the syntax of OPENXML, 
see OPENXML (Transact-SQL).

To write queries against an XML document by using OPENXML, 
you must first call sp_xml_preparedocument. This parses the 
XML document and returns a handle to the parsed document 
that is ready for consumption. The parsed document is a 
document object model (DOM) tree representation of various 
nodes in the XML document. The document handle is passed to 
OPENXML. OPENXML then provides a rowset view of the 
document, based on the parameters passed to it.