title: How to get value from previous field to new field
body: <p>Is there any way to call value from previous field to the new field by using trigger?
  i have tried with following method and this method is working perfectly with first row but when i moved to second row it automatically copy data from "remaining" to "monthly" field:</p>
  
  <pre><code>BEGIN
  IF (:REMAINING IS NULL) THEN
  :REMAINING=:MONTHLY-:FEE;
  NEXT_ITEM;
  :MONTHLY:=:REMAINING;
  END IF;
  END;
  </code></pre>