Add attribute to xmltype with value taken from sequence

Question

I am using Oracle XE in version 11.2.

I have such kind of XML:

<root>
    <x a="a"/>
    <x a="b"/>
    <x a="c"/>
</root>

No I would like to add attribute b to each element x with value taken from sequence, but it should take new value for each element. Expected result is:

<root>
    <x a="a" b="1"/>
    <x a="b" b="2"/>
    <x a="c" b="3"/>
</root>

I've found that to add attribute to XML I can use insertchildxml but in is adding the same (frist) value from sequence to all attributes b. I can't find how to call this function for each individual element x.

I will be grateful for any help.

Answer 1

I've finaly found some solution and key to it was to use XMLTable() function. Here is my code:

declare
v_inXML xmltype;
  v_tmpXML xmltype;
  v_withIdXML xmltype;
  v_outXML xmltype;
BEGIN   
  v_inXML := XMLType('<root><x a="a"/><x a="b"/><x a="c"/></root>');
  v_withIdXML := XMLType('<root/>'); 
  v_outXML := XMLType('<root/>');

  for c_rec in (
    select *
    from   XMLTable('for $i in /root/x
          return $i'
          passing  v_inXML
          columns x xmltype path '/x'
    )
  )
  loop
    select insertchildxml(c_rec.x,'//x', '@b', pckg_ent_pk_seq.nextval) into v_tmpXML from dual;      
    select insertchildxml(v_withIdXML, '/root', 'x', v_tmpXML) into v_withIdXML from dual;    
  end loop;

  select updatexml(v_outXML, '/root', v_withIdXML) into v_outXML from dual;

  dbms_output.put_line(v_outXML.getClobVal());
END;

And the result is:

<root><x a="a" b="92"/><x a="b" b="93"/><x a="c" b="94"/></root>