.dbf tables and Null

[Ethan Furman]

Mornin'!  and a good one, too, I hope.

Question for you...

First part of the question:  What is the general value in having Null 
capability for fields?

Second part:  Is there a tangible difference between Null, and the 
nothing of 0, '', False, etc, in python?

Third part:  If there is a tangible difference, do those of us who use 
python and these old, refuse-to-die, .dbf files actually have need of, 
or have tables including, Null values?

P.S. part (for John Machin, if he sees this  ;)
Will the dbf package you are working on support Null values?

Any and all information appreciated!

~Ethan~