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>
>
> 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.
>
>
>
> 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.
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