Re: Does entity integrity imply entity identity?

From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Wed, 05 Aug 2009 21:25:12 -0300
Message-ID: <4a7a22e9$0$23782$9a566e8b_at_news.aliant.net>


Bob Badour wrote:

> Mr. Scott wrote:
>

>> "Bob Badour" <bbadour_at_pei.sympatico.ca> wrote in message 
>> news:4a799414$0$23781$9a566e8b_at_news.aliant.net...
>>
>>> Mr. Scott wrote:
>>>
>>>> "Bob Badour" <bbadour_at_pei.sympatico.ca> wrote in message 
>>>> news:4a784836$0$23766$9a566e8b_at_news.aliant.net...
>>>>
>>>>> Mr. Scott wrote:
>>>>>
>>>>>>> The entity integrity rule is generally presented as a subrule 
>>>>>>> under Codd's rule 10.
>>>>>
>>>>> I don't know why you would say that when the description of the 
>>>>> so-called "entity integrity" basically restates Rule 2 verbatim.
>>>>
>>>> I don't think that's true.  Although the entity integrity rule 
>>>> implies the guaranteed access rule, the guaranteed access rule 
>>>> doesn't imply the entity integrity rule.  The guaranteed access rule 
>>>> doesn't say anything at all about nulls.
>>>
>>> As Martha would say: This is a good thing. Null was a bad idea in the 
>>> first place.
>>
>> Why was it a bad idea?

>
> Entire books have been written on that subject. I suggest you read one
> or two of them. See for example Date's various _Writings..._ books.
>
>
>> Is there a reasonable alternative?

>
> Yes. Nothing at all is a reasonable alternative to anything as bad as
> null. If it ain't broken, don't try to fix it. If it is broken, don't
> break it worse.

Perhaps I should clarify: Your question amounts to asking if one has a reasonable alternative to poking oneself in the eye with an icepick. Received on Thu Aug 06 2009 - 02:25:12 CEST

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