dbms_xmldom - How to get the <?xml tag - oracle

Question

I am trying to get the line <?xml ....?> at the start of the XML document using the PL/SQL Package dbms_xmldom. Here is the code so far
declare
l_dom dbms_xmldom.DOMDocument;
l_clob clob;
l_node dbms_xmldom.DOMNode;
begin
l_dom := dbms_xmldom.newDomDocument;
l_node := dbms_xmldom.makeNode(l_dom);
l_node := dbms_xmldom.appendChild(l_node,
dbms_xmldom.makeNode(
dbms_xmldom.createElement(l_dom, 'root')
)
);
dbms_lob.createtemporary(l_clob, true);
dbms_xmldom.writeToClob(l_dom, l_clob);
dbms_output.put_line(l_clob);
end;
The output is:
<root/>
Expect:
<?xml version="1.0" encoding="UTF-8"?>
<root/>
Any pointers on how to do this would get great.

Answer 1

Just for the record - here is what you need to add
dbms_xmldom.setVersion(l_dom, '1.0" encoding="UTF-8');
after creating the document

Answer 2

The prolog is usually added automatically by XML serialization, so you shouldn't need to add it yourself, but if you want to you can with XMLRoot.
Your method for generating XML is quite inefficient. You should be looking at XMLElement, XMLForest, XMLAgg etc.
Here's a simple root and child example, with prolog in one line of code.
select XMLRoot(XMLElement("root", XMLElement("child", 12)), version '1.0') from dual
<?xml version="1.0"?>
<root>
<child>12</child>
</root>