PLSQL :NEW and :OLD

Question

Can anyone help me understand when to use :NEW and :OLD in PLSQL blocks, I\'m finding it very difficult to understand their usage.

Answer 1

:old and :new are pseudo records referred to access row level data when using row level trigger.

•:old - refers to Old Value •:new - refers to New value

for example:

CREATE OR REPLACE TRIGGER mytrig BEFORE
  INSERT OR
  UPDATE
    ON mytab FOR EACH ROW
BEGIN
  IF INSERTING THEN
    SELECT trunc(sysdate), trunc(sysdate) INTO :new.created, :NEW.last_updated FROM DUAL;
  END IF; --INSERTING

  IF UPDATING THEN

      SELECT trunc(sysdate) INTO :NEW.last_updated FROM DUAL;

  END IF; --UPDATING

END;

Hope this explains the concept of old and new.