Help for pl/sql block

Question

need help on this to performance better.
DECLARE
     FILE_READ UTL_FILE.FILE_TYPE;
     LOCATION VARCHAR2(128):='D:\PLSQL';
     FILENAME VARCHAR2(128):='TEST.txt';
     OPEN_MODE VARCHAR2(128):='r';
     V_LINE VARCHAR2(128);
     V_ORDERCODE CHAR(15);
     V_REST     CHAR(100);     
     V_OWNERCODE     CHAR(5);
     CURSOR C_ORD IS
     SELECT ORD.ORDERID,ORD.OWNERID
     FROM ORDERS ORD,OWNERS OWN
     WHERE ORD.ORDERCODE=V_ORDERCODE
     AND ORD.OWNERID=OWN.OWNERID
     AND OWN.OWNERCODE=V_OWNERCODE
     AND ORD.STATUS=10
     ORDER BY ORD.SEQ DESC;
     R_ORD          C_ORD%ROWTYPE;     
BEGIN
     FILE_READ:=UTL_FILE.FOPEN(LOCATION,FILENAME,OPEN_MODE);
     LOOP
          BEGIN
               UTL_FILE.GET_LINE(FILE_READ,V_LINE);
               EXCEPTION
                    WHEN NO_DATA_FOUND THEN
                         EXIT;
          END;
          V_OWNERCODE:=RTRIM(SUBSTR(V_LINE,0,5));
          V_ORDERCODE:=SUBSTR(V_LINE,7,15);
          V_REST:=SUBSTR(V_LINE,23,LENGTH(RTRIM(LTRIM(V_LINE))));
          OPEN C_ORD;
          FETCH C_ORD INTO R_ORD;
          IF C_ORD%FOUND THEN
               UPDATE ORDERS SET UNDEF10=RTRIM(V_REST) WHERE ORDERCODE=V_ORDERCODE AND OWNERID=R_ORD.OWNERID;
          END IF;
          CLOSE C_ORD;
     END LOOP;
     UTL_FILE.FCLOSE(FILE_READ);
EXCEPTION
     WHEN UTL_FILE.INVALID_MODE THEN
          RAISE_APPLICATION_ERROR(-20001,'INVALID_MODE');
     WHEN UTL_FILE.READ_ERROR THEN
          RAISE_APPLICATION_ERROR(-20002,'READ_ERROR');
     WHEN UTL_FILE.INVALID_PATH THEN
          RAISE_APPLICATION_ERROR(-20003,'INVALID_PATH');
     WHEN UTL_FILE.INVALID_FILEHANDLE THEN
          RAISE_APPLICATION_ERROR(-20004,'INVALID_FILEHANDLE');
     WHEN UTL_FILE.INVALID_OPERATION THEN
          RAISE_APPLICATION_ERROR(-20005,'INVALID_OPERATION');
     WHEN UTL_FILE.WRITE_ERROR THEN
          RAISE_APPLICATION_ERROR(-20006,'WRITE_ERROR');
     WHEN UTL_FILE.INTERNAL_ERROR THEN
          RAISE_APPLICATION_ERROR(-20007,'INTERNAL_ERROR');
     WHEN OTHERS THEN
          RAISE_APPLICATION_ERROR(-20008,SQLERRM);
END;

Answer 1

My obersvations for poor performance (although you have not defined what is "poor")
1. Why ORDER BY in cursor ?
2. Why CURSOR itself ?
It seems to me that all you are doing is checking whether the SQL (in cursor) returns any data. If yes, yo are updating ORDERS table. You should be able to eliminate cursor entirely. That will save all processing on cursor.
If you can explain (in english) what you are trying to achieve, I may be able to provide better solution.