SQL> declare
  2  type typ_dup1 is table of dup1%rowtype;
  3  v_dup1 typ_dup1;
  4  begin
  5  select * bulk collect into v_dup1 from dup1;
  6  dbms_output.put_line(v_dup1.a);
  7  end;
  8  /
dbms_output.put_line(v_dup1.a);
                            *
ERROR at line 6:
ORA-06550: line 6, column 29:
PLS-00302: component 'A' must be declared
ORA-06550: line 6, column 1:
PL/SQL: Statement ignored

SQL> desc dup1
 Name       Null?    Type                                                               
 ----------------- ------------
 A                            NUMBER

DECLARE
  TYPE TYP_DUP1 IS TABLE OF DUP1%ROWTYPE;
   V_DUP1  TYP_DUP1;
BEGIN
  SELECT *
  BULK COLLECT INTO V_DUP1
  FROM   DUP1;
  
  DBMS_OUTPUT.PUT_LINE(V_DUP1.A);
END;

DECLARE
  TYPE TYP_DUP1 IS TABLE OF DUP1%ROWTYPE;
   V_DUP1  TYP_DUP1;
BEGIN
  SELECT A
  BULK COLLECT INTO V_DUP1
  FROM   DUP1;
  
  FOR I IN V_DUP1.FIRST.. V_DUP1.LAST LOOP
    DBMS_OUTPUT.PUT_LINE(V_DUP1(I).A);
  END LOOP;
END;
/

SQL> select * from DUP1;
         A
----------
        10

1 row selected.

SQL> DECLARE
  2    TYPE TYP_DUP1 IS TABLE OF DUP1%ROWTYPE;
  3     V_DUP1  TYP_DUP1;
  4  BEGIN
  5    SELECT A
  6    BULK COLLECT INTO V_DUP1
  7    FROM   DUP1;
  8    
  9    FOR I IN V_DUP1.FIRST.. V_DUP1.LAST LOOP
 10      DBMS_OUTPUT.PUT_LINE(V_DUP1(I).A);
 11    END LOOP;
 12  END;
 13  /
10

PL/SQL procedure successfully completed.

SQL> delete DUP1;

1 row deleted.

SQL> DECLARE
  2    TYPE TYP_DUP1 IS TABLE OF DUP1%ROWTYPE;
  3     V_DUP1  TYP_DUP1;
  4  BEGIN
  5    SELECT A
  6    BULK COLLECT INTO V_DUP1
  7    FROM   DUP1;
  8    
  9    FOR I IN V_DUP1.FIRST.. V_DUP1.LAST LOOP
 10      DBMS_OUTPUT.PUT_LINE(V_DUP1(I).A);
 11    END LOOP;
 12  END;
 13  /
DECLARE
*
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error
ORA-06512: at line 9

SQL> select * from dup1;

no rows selected

SQL> DECLARE
  2    TYPE TYP_DUP1 IS TABLE OF DUP1%ROWTYPE;
  3     V_DUP1  TYP_DUP1;
  4  BEGIN
  5    SELECT A
  6    BULK COLLECT INTO V_DUP1
  7    FROM   DUP1;
  8    FOR I IN 1.. V_DUP1.COUNT LOOP
  9      DBMS_OUTPUT.PUT_LINE(V_DUP1(I).A);
 10    END LOOP;
 11* END;
SQL> /

PL/SQL procedure successfully completed.