You can retrieve XML data as an entire document or as query results.
XML values returned from the database might not be well-formed XML documents as defined by the XML 1.0 and XML 1.1 specifications. For example, XML queries can return sequences or atomic values that might not have a well-formed XML representation. Note that parsing errors can occur in these cases. You can either include these results into other XML documents through entity references or using string concatenation. You can also modify queries so that well-formed XML is returned.
XML values are always returned in non-Field Mode.