Oracle Pl/SQL: Loop through XMLTYPE nodes

问题:

I have a XMLTYPE with the following content:

<?xml version="1.0"?>
    <users>
        <user>
            <name>user1</name>
        </user>
        <user>
            <name>user2</name>
        </user>
        <user>
            <name>user3</name>
        </user>
    </users>

How can I loop in PL/SQL through all the elements "user"? Thanks

回答1:

You can loop through the elements using EXTRACT and XMLSequence (splits the XML into distinct chunks -- here users) like this:

SQL> SELECT extractvalue(column_value, '/user/name') "user"
  2    FROM TABLE(XMLSequence(XMLTYPE(
  3                 '<?xml version="1.0"?>
  4                     <users>
  5                         <user>
  6                             <name>user1</name>
  7                         </user>
  8                         <user>
  9                             <name>user2</name>
 10                         </user>
 11                         <user>
 12                             <name>user3</name>
 13                         </user>
 14                     </users>').extract('/users/user'))) t;

user
--------
user1
user2
user3

回答2:

You can use XQuery. Check out the select statement below. v_xml_doc is the XMLTYPE variable containing the XML data.

select name
from   XMLTable('for $i in /users/user
                            return $i'
                            passing   v_xml_doc
                            columns   name varchar2(200) path 'name'
               )

回答3:

How about this:

PROCEDURE xmltest IS
  v_userlist XMLType;
  v_count NUMBER(38) := 1;
BEGIN
  /* define XML variable */
  v_userlist := XMLType('<?xml version="1.0"?>
    <users>
        <user>
            <name>user1</name>
        </user>
        <user>
            <name>user2</name>
        </user>
        <user>
            <name>user3</name>
        </user>
    </users>');

  /* for each user, print out their name (each element can be extracted using xpath '//user[1]' '//user[2]' etc) */
  WHILE v_userlist.existsNode('//user[' || v_count || ']') = 1 LOOP
    dbms_output.put_line(v_userlist.extract('//user[' || v_count || ']/name/text()').getStringVal());
    v_count := v_count + 1;
  END LOOP;
END;

回答4:

select xt.* from xmltable('/users/user' passing xmltype('<users>
    <user>
        <name>user1</name>
    </user>
    <user>
        <name>user2</name>
    </user>
    <user>
        <name>user3</name>
    </user>
</users>') columns name varchar2(10) path 'name' ) xt 

回答5:

ITS VERY GOOD!!

CADENA   CLOB;
BEGIN
   SELECT CASE
             WHEN EXISTSNODE (:NEW.MENSAJE, '/Body') <> 0 THEN 'ERROR'
             ELSE NULL
          END
     INTO :NEW.DESCRIPCION_ERROR
     FROM DUAL;

   CADENA := :NEW.MENSAJE.EXTRACT ('/Body/xmlOriginal/text()').getStringVal ();
   CADENA := REPLACE (CADENA, '&lt;', '<');
   CADENA := REPLACE (CADENA, '&gt;', '>');