WHERE CURRENT OF raising and invalid rowid error - oracle

Question

I'm trying to increase the age of every customer by 1 and display them; using a cursor.
This is the Table structure.
Select * from customers;
+----+----------+-----+-----------+----------+
| ID | NAME | AGE | ADDRESS | SALARY |
+----+----------+-----+-----------+----------+
| 1 | Ramesh | 32 | Ahmedabad | 2000.00 |
| 2 | Khilan | 25 | Delhi | 1500.00 |
| 3 | kaushik | 23 | Kota | 2000.00 |
| 4 | Chaitali | 25 | Mumbai | 6500.00 |
| 5 | Hardik | 27 | Bhopal | 8500.00 |
| 6 | Komal | 22 | MP | 4500.00 |
Here is my code:
DECLARE
c_id customers.id%TYPE;
c_name customers.name%TYPE;
c_age customers.age%TYPE;
CURSOR c1 IS
SELECT id, name, age
FROM customers
FOR UPDATE OF salary;
BEGIN
OPEN c1;
LOOP
FETCH c1 INTO c_id, c_name, c_age;
UPDATE customers
SET age = age + 1
WHERE CURRENT OF c1;
EXIT WHEN c1%NOTFOUND;
dbms_output.put_line( c_id || ' ' || c_name || ' ' || c_age );
END LOOP;
CLOSE c1;
END;
/
However, I am getting the following error:
Error report:
ORA-01410: invalid ROWID
ORA-06512: at line 13
01410. 00000 - "invalid ROWID"
*Cause:
*Action:
1 Ramesh 32
2 Khilan 25
3 kaushik 23
4 Chaitali 25
5 Hardik 27
6 Komal 22
Why is this happening and how can I stop it?

Answer 1

You have your exit in the wrong place; it should be straight after the fetch. You are processing your six real rows properly, but then you have a seventh fetch - after which %notfound will be true - so there is no 'current' row to update. You need to exit before you try to do anything with that invalid row.
BEGIN
OPEN c1;
LOOP
FETCH c1 INTO c_id, c_name, c_age;
EXIT WHEN c1%NOTFOUND;
UPDATE customers
SET age = age + 1
WHERE CURRENT OF c1;
dbms_output.put_line( c_id || ' ' || c_name || ' ' || c_age );
END LOOP;
CLOSE c1;
END;
Hopefully this is just an exercise, as it's not a very efficient way to do the updates.