Creates an XML processing instruction node with the name determined by XML_PI_target.
XMLPI creates an XML processing instruction node with the name specified by XML_PI_target. char_value_expr is evaluated to a character string value using the rules for converting SQL data type values to XML values. A processing instruction node is constructed from the name and character string value so that its serialization is <? name character-string-value ?>. If this is not a well-formed XML 1.1 PI, an error is raised.
The return value is of XML type. The return value is based on the RETURNING clause. If the clause is not specified, the default is RETURNING SEQUENCE.