>>Hi all,
>>
>>What is the advantage when we allowing Null data type to each data field?
>>
>Aston,
>
>Null's are usefull when value in a field can be unknown. It mostly used with datetime data type to represent unknown or not entered yet value. I tend to use them only if I've to because they can be a pain to work with.


They also require some extra overhead in processing. So I recommend that you only use them if needed.