Wanted to fetch data from ref cursor to nested pl/sql table getting an erro

Question

create or replace type "DEPT12" as object(dno number(2),dname varchar2(30),loc varchar2(50));
create or replace type dept_tab as table of "DEPT12"
create or replace type "LOC12" as object(locno number,loc_name varchar2(100))
create or replace type loc_tab as table of "LOC12"
create or replace type dept_loc_rec1 as object (dept_dt dept_tab,eno number,loc_dt loc_tab);
create type dept_loc_tb as table of dept_loc_rec1
create table dept_loc_tb_bk1(dept_dt dept_tab,eno number,loc_dt loc_tab)
NESTED TABLE dept_dt
STORE AS dept_tab12,
NESTED TABLE loc_dt
STORE AS loc_tab12
insert into dept_loc_tb_bk1 values(dept_tab(dept12(3,'ABD','LOC')
,dept12(4,'ABD','LOC')
,dept12(5,'ABD','LOC')),3,loc_tab(loc12(21,'AAB'),
loc12(22,'AAB'),
loc12(23,'AAB')));
when I am trying to fetch data from ref cursor to pl/sql table which i am getting an error ora-06504: pl/sql : Return types of result set variables or query do not match.
I have created a nested table of same as the nested pl/sql object table dept_loc_tb and i have declared the lv_dept_loc_tb of same dept_loc_tb but getting an above error when trying to fetch into that variable.
Please any one who can solve my problem.
declare
type cr is ref cursor;
cr_obj cr;
lv_dept_loc_tb dept_loc_tb;
begin
open cr_obj for select dept_dt,eno,loc_dt from dept_loc_tb_bk1;
fetch cr_obj bulk collect into lv_dept_loc_tb;
close cr_obj;
end;

Answer 1

Your query selects 3 separate columns therefore requires 3 collections of corresponding types. You want to treat those 3 columns as an object of DEPT_LOC_REC1 type:
SQL> declare
  2  type cr is ref cursor;
  3  cr_obj cr;
  4 
  5  lv_dept_loc_tb dept_loc_tb;
  6 
  7  begin
  8  open cr_obj for select dept_dt,eno,loc_dt from dept_loc_tb_bk1;
  9  fetch cr_obj bulk collect into lv_dept_loc_tb;
10  close cr_obj;
11  end;
12  /
declare
ERROR at line 1:
ORA-06504: PL/SQL: Return types of Result Set variables or query do not match
ORA-06512: at line 9
SQL> declare
  2  type cr is ref cursor;
  3  cr_obj cr;
  4 
  5  lv_dept_loc_tb dept_loc_tb;
  6 
  7  begin
  8  open cr_obj for select DEPT_LOC_REC1(dept_dt,eno,loc_dt) from dept_loc_tb_bk1;
  9  fetch cr_obj bulk collect into lv_dept_loc_tb;
10  close cr_obj;
11  end;
12  /
PL/SQL procedure successfully completed.
SQL> SY.
P.S. Discover sys_refcursor.