title: how to use trigger and cursor in combined with for loop in oracle?
body: <p>assuming two table </p>
  
  <pre><code> 1.student(roll_no, class, credits)
   2.class(class, total_student, Total_credits)
  </code></pre>
  
  <p>how to create trigger using cursor on student table which will <strong>update class</strong> with <strong>Total no of Student's</strong> and <strong>their total credits</strong> ?
  on each insertion or deletion </p>