Explicit Cursor - Simple Loop
Oracle provides three types of cursors namely SIMPLE LOOP, WHILE LOOP and FOR LOOP. These loops can be used to process multiple rows in the cursor. Here I will modify the same example for each loops to explain how to use loops with cursors.
Cursor with a Simple Loop:
1> DECLARE
2> CURSOR emp_cur IS
3> SELECT first_name, last_name, salary FROM emp_tbl;
4> emp_rec emp_cur%rowtype;
5> BEGIN
6> IF NOT sales_cur%ISOPEN THEN
7> OPEN sales_cur;
8> END IF;
9> LOOP
10> FETCH emp_cur INTO emp_rec;
11> EXIT WHEN emp_cur%NOTFOUND;
12> dbms_output.put_line(emp_cur.first_name || ' ' ||emp_cur.last_name
13> || ' ' ||emp_cur.salary);
14> END LOOP;
15> END;
16> /
In the above example we are using two cursor attributes %ISOPEN and %NOTFOUND.
In line no 6, we are using the cursor attribute %ISOPEN to check if the cursor is open, if the condition is true the program does not open the cursor again, it directly moves to line no 9.
In line no 11, we are using the cursor attribute %NOTFOUND to check whether the fetch returned any row. If there is no rows found the program would exit, a condition which exists when you fetch the cursor after the last row, if there is a row found the program continues.
We can use %FOUND in place of %NOTFOUND and vice versa. If we do so, we need to reverse the logic of the program. So use these attributes in appropriate instances.
