Table updation problem

hello

i have created one materail today, when i saw the table MARA i have seen the created date 16.05.2007 , when i saw the table MARD in this "created on" field(ERDSA) is giving blank value 00.00.0000 it mean that table is not updated

after creation of materail how to update that MARD table and Field ERDSA , bcz it should show me creation date plz give answer

im awaiting your relpy

regards

sapman