Retrieve value of an xml element in Oracle PL SQL

Question

Does anybody know how to retrieve the values of <ZIPCODE> and <CITY> using PL/SQL? I have followed a tutorial over the net, however, it can retrieve the element names, but not their values. Any of you know what seems to be the problem? I have already consulted Google (the internet's well kept secret) over this but no luck :(

<Zipcodes>
  <mappings Record="4">
    <STATE_ABBREVIATION>CA</STATE_ABBREVIATION>
    <ZIPCODE>94301</ZIPCODE>
    <CITY>Palo Alto</CITY>
  </mappings>
</Zipcodes>

here's the sample code:

-- prints elements in a document
PROCEDURE printElements(doc DBMS_XMLDOM.DOMDocument) IS
    nl  DBMS_XMLDOM.DOMNodeList;
    n   DBMS_XMLDOM.DOMNode;
    len number;
BEGIN
    -- get all elements
    nl   := DBMS_XMLDOM.getElementsByTagName(doc, '*');

    len  := DBMS_XMLDOM.getLength(nl);

    -- loop through elements
    FOR i IN 0 .. len - 1 LOOP
        n := DBMS_XMLDOM.item(nl, i);

        testr := DBMS_XMLDOM.getNodeName(n) || ' ' || DBMS_XMLDOM.getNodeValue(n);

        DBMS_OUTPUT.PUT_LINE (testr);
    END LOOP;

    DBMS_OUTPUT.PUT_LINE ('');
END printElements;

Answer 1

You need to change the line

testr := DBMS_XMLDOM.getNodeName(n) || ' ' || DBMS_XMLDOM.getNodeValue(n);

to

testr := DBMS_XMLDOM.getNodeName(n) || ' ' || DBMS_XMLDOM.getNodeValue(DBMS_XMLDOM.getFirstChild(n));

In XML DOM, elements don't have any 'value' to speak of. Element nodes contain Text nodes as children, and it is these nodes that contain the values you want.

EDIT (in response to Tomalak's comment): I'm not aware of any functions in DBMS_XMLDOM to obtain the combined value of all the child text nodes of an element. If that's what you need, then you may well need to use something like the following function:

CREATE OR REPLACE FUNCTION f_get_text_content (
    p_node          DBMS_XMLDOM.DOMNode
) RETURN VARCHAR2
AS
  l_children        DBMS_XMLDOM.DOMNodeList;
  l_child           DBMS_XMLDOM.DOMNode;
  l_text_content    VARCHAR2(32767);
  l_length          INTEGER;
BEGIN
  l_children := DBMS_XMLDOM.GetChildNodes(p_node);
  l_length := DBMS_XMLDOM.GetLength(l_children);
  FOR i IN 0 .. l_length - 1 LOOP
    l_child := DBMS_XMLDOM.Item(l_children, i);
    IF DBMS_XMLDOM.GetNodeType(l_child) = DBMS_XMLDOM.TEXT_NODE THEN
      l_text_content := l_text_content || DBMS_XMLDOM.GetNodeValue(l_child);
    END IF;
  END LOOP;
  RETURN l_text_content;
END f_get_text_content;
/