set serveroutput on;
declare
    xmlString CLOB;
    amount integer:= 255;
    position integer := 1;
    charString varchar2(255);
    len integer;

    l_ctx  dbms_xmlgen.ctxHandle;

begin

    l_ctx := dbms_xmlgen.newcontext('select * from xxa_article');
    
    xmlString := dbms_xmlgen.getXML(l_ctx  ); -- This gets the XML out

    len := dbms_lob.getlength  (xmlString);

    dbms_lob.open(xmlString,DBMS_LOB.LOB_READONLY); 
    loop
        dbms_lob.read(xmlString,amount,position,charString);      -- read the lob data
        dbms_output.put_line(charString);
        position := position + amount;
        EXIT when position > len;
    end loop;

    dbms_lob.close(xmlString);
    dbms_xmlgen.closecontext(l_ctx);
    
    EXCEPTION
    WHEN OTHERS THEN
    DECLARE
    ERR_NUM NUMBER:=SQLCODE;
    ERR_MSG VARCHAR2(200):=SQLERRM;
    BEGIN
     DBMS_OUTPUT.PUT_LINE('ORA ERROR № ' || ERR_NUM);
     DBMS_OUTPUT.PUT_LINE('ORA ERROR MESSAGE ' || ERR_MSG);
     ROLLBACK;
    END;
end;

<?xml version="1.0"?>
<ROWSET>
 <ROW>
  <IDD>111</IDD>
  <NAME_TOVAR>PEN BLUE</NAME_TOVAR>
  <ID_VID>111</ID_VID>
  <PRICE>35</PRICE>
  <DATE_INSERT>17.07.17</DATE_INSERT>
  <WHO_INSERT>USR1</WHO_INSERT>
  <DATE_UPDATE>17.07.17</DATE_UPDATE>
  <WHO_UPDATE
>USR1</WHO_UPDATE>
 </ROW>
</ROWSET>

<?xml version="1.0"?>
<ROWSET>
 <ROW>
  <IDD>111</IDD>
  <NAME_TOVAR>PEN BLUE</NAME_TOVAR>
  <ID_VID>111</ID_VID>
  <PRICE>35</PRICE>
  <DATE_INSERT>17.07.17</DATE_INSERT>
  <WHO_INSERT>USR1</WHO_INSERT>
  <DATE_UPDATE>17.07.17</DATE_UPDATE>
  <WHO_UPDATE>USR1</WHO_UPDATE>
 </ROW>
</ROWSET>