The use of NULLs is one of those religious things. Some people won't touch them, others will. Personally, I use NULLs.

As for having them in a FK, sure.

-Mike



>>If you're using FK constraints, you will not be able to have an FK of 0 unless there is actually a row with an ID of 0 in the parent table. OTOH, you can have a FK of NULL.
>>
>>-Mike
>>
>>>>>>Hi all,
>>>>>>
>>>>>>What is the advantage when we allowing Null data type to each data field?
>>>>>>
>>>>>Aston,
>
>Thanks, Mike.
>Then going back to the original question of this thread would you say that it is best to allow Nulls in foreign key fields? Otherwise you would have to maintain a default, meaningless record in the parent.
>
>Regards,