Hi,
I am often running into this type of design, but would it be a good
design. Normally you design tables related to each other and having e.g.
parameter tables like a country-table holding country names with their
country-id's; and you will find these country-ids back in other tables,
which have the foreign key country_id related to the primary key
country_id. (voila).
Would it still be a good design if you would except NULL values in a
related field which hold the foreign key; because it could be possible
that nobody would enter or select a country. The trouble would be i
guess, consistency; because you now have a value (NULL) which is not
present in the country table.
The country_id is an example, but you can guess there would be more
examples you can think of.
If I am not clear enough please let me know; and I can be more specific.
Danny
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