The PARSE-AS-XML directive parses an XML document. The directive operates on a column to parse that into an XML VTD object; that can be further queried using the XPATH directive.
parse-as-xml <column>
The <column> is the name of the column in the record that is an XML document.
The PARSE-AS-XML directive efficiently parses and represents an XML document using an in-memory structure that can then be queried using other directives.