I've been building databases since I started working with PFS File in the 1980's. :w00t:

It seems like there is a literal meaning for NULL, which is "unknown", and a practical meaning, which is "data is not present in this field".

If I declare a CreateDate field as: [CreateDate] [datetime] NULL

When I select from that table and see NULL in some of the columns for the CreateDate field, I don't start thinking "Gee, I wonder what's in those fields because it's unknown". I know perfectly well that there is no data present because I allowed the record to be saved without requiring data in that field.