Re: Some Humor
From: Jan Hidders <jan.hidders_at_REMOVETHIS.pandora.be>
Date: Tue, 21 Jun 2005 19:44:40 GMT
Message-ID: <I6_te.126589$qm.6955067_at_phobos.telenet-ops.be>
>> Jan Hidders wrote:
>>
>>> Dan wrote:
>>>
>>>> ThirdNormalForm:
>>>>
>>>> 1. The key
>>>> 2. The whole key
>>>> 3. And nothing but the key
>>>>
>>>> So help me Codd.
>>>
>>> Pop-quiz! Does this describe 3NF or BCNF? Explain Why.
>>
>> BCNF.
>>
>> IIRC, 3NF permits an FD that references part of a candidate key, and
>> therefore fails on the third point.
Date: Tue, 21 Jun 2005 19:44:40 GMT
Message-ID: <I6_te.126589$qm.6955067_at_phobos.telenet-ops.be>
Dan wrote:
> On 6/21/2005 12:22 AM, Jonathan Leffler wrote:
>> Jan Hidders wrote:
>>
>>> Dan wrote:
>>>
>>>> ThirdNormalForm:
>>>>
>>>> 1. The key
>>>> 2. The whole key
>>>> 3. And nothing but the key
>>>>
>>>> So help me Codd.
>>>
>>> Pop-quiz! Does this describe 3NF or BCNF? Explain Why.
>>
>> BCNF.
>>
>> IIRC, 3NF permits an FD that references part of a candidate key, and
>> therefore fails on the third point.
Well done! Actually the items should be preceded by "every attribute is determined by". In that case you get BCNF. If you change that to "every non-key attribute is determined by" then you get 3NF.
> Still funny though!
Yes, it is! Thank you.
- Jan Hidders