Varray of Object Type

Question

Hello,
I am still very new at PL/SQL so please bare with me if you can. I am trying to learn how to store data from an object in a single varray of objects. My code below is attempting to declare an object type with 3 instance attributes and 3 instance methods of getter and setter method.
Then i want to create a varray type to store an array of "Employee" object types.
From here i am trying to use a loop to retrieve the first 10 ename, empno, and sal records from the emp table and store them in the variable array of 10 elements.
Finally, I tried to use another loop to output the ename, empno, and sal in reverse order.
My object and my object body was created successfully with no errors.
The problem starts when I begin the anonymous block that creates the varray, this is where i get an error message at the end.
At the end of my code is the error message i get. Can anyone suggest to me what I am doing wrong, and/or what I can do to achieve this task.
SET SERVEROUTPUT ON
--create object
CREATE OR REPLACE TYPE Employee AS OBJECT(
  ename_obj VARCHAR2(10),
  empno_obj NUMBER(4),
  sal_obj NUMBER(7,2),
  MEMBER FUNCTION getename RETURN VARCHAR2,
  MEMBER FUNCTION getempno RETURN NUMBER,
  MEMBER FUNCTION getsal RETURN NUMBER);
--create object body
CREATE OR REPLACE TYPE BODY Employee AS
  MEMBER FUNCTION getename RETURN VARCHAR2 IS
  BEGIN
   RETURN ename_obj;
  END;
  MEMBER FUNCTION getempno RETURN VARCHAR2 IS
  BEGIN
   RETURN empno_obj;
  END;
  MEMBER FUNCTION getsal RETURN VARCHAR2 IS
  BEGIN
   RETURN sal_obj;
  END;
END;
--create varray of object and begin line 1 of ERROR Message--
1> DECLARE
2> TYPE tvrEmploy IS VARRAY(10) OF Employee;
3>  vClient    tvrEmploy;
4>    iCounter   integer:=1;
5>   CURSOR client_cursor IS
6>   SELECT ename, sal
7>    FROM emp
8>    WHERE rownum < 11;
9>  BEGIN
10>    vClient:=tvrEmploy(null,null,null,null,null,null,null,null,null,null) ;
11>    FOR i IN client_cursor LOOP
12>       vClient(iCounter).ename_obj:=i.ename;
13>      vClient(iCounter).empno_obj:=i.empno;
14>       vClient(iCounter).sal_obj:=i.sal;
15>       iCounter:=iCounter+1;
16>    END LOOP;
17>    FOR I IN REVERSE 1..10 LOOP
18>        dbms_output.put_line(to_char(I) ||' '|| vClient(I).ename_obj ||' '|| vClient(I).empno_obj ||' '||
          vClient(I).sal_obj);
19>    END LOOP;
20> END ;
21> /
--ERROR message below--
DECLARE
ERROR at line 1:
ORA-06530: Reference to uninitialized composite
ORA-06512: at line 12
Thank you again for your time and patience.
-Todd

Answer 1

Hi,
The error occurs on line 12, the first time through the loop, when you try to execute:
vClient(iCounter).ename_obj:=i.ename;
At that point, vClient (1) is not an Employee object; it's NULL.
Try this:
DECLARE
    TYPE tvrEmploy IS VARRAY(10) OF Employee;
    vClient    tvrEmploy;
    iCounter   integer := 1;
    CURSOR client_cursor IS
        SELECT  ename, sal
        ,       empno                                                 -- ADDED
   FROM    scott.emp
   WHERE   rownum < 11;
BEGIN
    vClient := tvrEmploy (null,null,null,null,null,null,null,null,null,null) ;  
    FOR i IN client_cursor LOOP
        vClient (iCounter) := Employee (i.ename, i.empno, i.sal);     -- CHANGED
        iCounter := iCounter + 1;
   END LOOP;
FOR I IN REVERSE 1..10 LOOP
       dbms_output.put_line(to_char(I) ||' '|| vClient(I).ename_obj ||' '|| vClient(I).empno_obj ||' '||
      vClient(I).sal_obj);
   END LOOP;
END ;