You should really avoid Null if you can.

The easiest way to do this is to have a default value that is "wrong". If you need a date you can over-write it, if not you leave it. You can then update your table with Null by replacing the "wrong" values with a SQL Update query.

BTW Using If x = Null will never work since the result of any operation including Null is always Null so True and False do not apply. You would have to use If IsNull(x) etc.

Cheers,

P.