Re: Base Normal Form
From: Jan Hidders <jan.hidders_at_REMOVETHIS.pandora.be>
Date: Thu, 07 Jul 2005 18:11:55 GMT
Message-ID: <Lfeze.139531$Jn.7313539_at_phobos.telenet-ops.be>
>>I'd like to suggest a new Normal Form definition, one that I'm calling Base
>>Normal Form, for lack of a better term.
>>
>>The purpose is NOT to advance theory any further. It's to make it easier to
>>teach introductory database design.
>>
>>Here it is:
>>
>>
>>A table is in base normal form if and only if it has at least one candidate
>>key.
Date: Thu, 07 Jul 2005 18:11:55 GMT
Message-ID: <Lfeze.139531$Jn.7313539_at_phobos.telenet-ops.be>
dawn wrote:
> David Cressey wrote: >
>>I'd like to suggest a new Normal Form definition, one that I'm calling Base
>>Normal Form, for lack of a better term.
>>
>>The purpose is NOT to advance theory any further. It's to make it easier to
>>teach introductory database design.
>>
>>Here it is:
>>
>>
>>A table is in base normal form if and only if it has at least one candidate
>>key.
> > I think that what you are describing is a mathematical function > (sometimes referred to as a mapping), perhaps?
I think that would be very confusing. First, his table actually has ordering, functions don't. Second, functions are binary relations, and even though you could interpret every n-ary relation as a binary relation, that is different from actually being the same. Finally, if there are multiple candidate keys then it actually represents several functions. It's really not a good idea to confuse the concept of relation and function.
- Jan Hidders