ORA-06530: Reference to uninitialized composite

Question

I have,
Created an Object:
CREATE OR REPLACE  TYPE opt_val_rec AS  OBJECT (
    parametervalue     VARCHAR2(1),
    PARAMETERID          varchar2(4000)
    );Created a table type:
     create  OR REPLACE  type  OPTVAL_TAB as  table of OPT_VAL_REC;
     Procedure to get the values into table type:
Create or replace  procedure test_parm_val (id in varchar2 ,result out  varchar2) as
pos number:=0;
  test_paramval                                 OPTVAL_TAB:= OPTVAL_TAB (null);
paramval_ord   OPTVAL_TAB:= OPTVAL_TAB (null);
begin
for I in (select DISTINCT param_name from  param_tbl)
loop
test_paramval.extend(10);
POS :=POS+1;
test_paramval (POS).PARAMETERVALUE:= get_param_val_fnc(id,I.PARAM_NAME);
test_paramval(POS). parameterid:=I.PARAM_NAME;
end loop;
SELECT CAST (MULTISET( SELECT  pv.PARAMETERVALUE,
                                   pv.parameterid
                            FROM TABLE (PARAMVAL)pv
                                                                                                  ORDER BY pv.PARAMETERVALUE)
                         AS OPTVAL_TAB)
    INTO paramval_ord
    FROM dual;*/
exception
when others then
NULL;
End;
end test_parm_valNow when executing the procedure, facing the above error mentioned in the subject.
Please help.

Answer 1

You initialized collection but not the object:
SQL> declare
  2      pos number:=0;
  3      test_paramval OPTVAL_TAB:= OPTVAL_TAB (null);
  4  begin
  5      test_paramval.extend(10);
  6      POS :=POS+1;
  7      test_paramval (POS).PARAMETERVALUE:= 'X';
  8      test_paramval(POS). parameterid:='Y';
  9  end;
10  /
declare
ERROR at line 1:
ORA-06530: Reference to uninitialized composite
ORA-06512: at line 7
SQL> declare
  2      pos number:=0;
  3      test_paramval OPTVAL_TAB:= OPTVAL_TAB (null);
  4  begin
  5      test_paramval.extend(10);
  6      POS :=POS+1;
  7      test_paramval (POS) := opt_val_rec(null,null);
  8      test_paramval (POS).PARAMETERVALUE:= 'X';
  9      test_paramval(POS). parameterid:='Y';
10  end;
11  /
PL/SQL procedure successfully completed.
SQL> -- or better
SQL> declare
  2      pos number:=0;
  3      test_paramval OPTVAL_TAB:= OPTVAL_TAB (null);
  4  begin
  5      test_paramval.extend(10);
  6      POS :=POS+1;
  7      test_paramval (POS) := opt_val_rec('X','Y');
  8  end;
  9  /
PL/SQL procedure successfully completed.
SQL> So change:
test_paramval (POS).PARAMETERVALUE:= get_param_val_fnc(id,I.PARAM_NAME);
test_paramval(POS). parameterid:=I.PARAM_NAME;to
test_paramval(POS) := opt_val_rec(get_param_val_fnc(id,I.PARAM_NAME),I.PARAM_NAME);SY.