Re: Does entity integrity imply entity identity?
From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Wed, 05 Aug 2009 11:15:40 -0300
Message-ID: <4a799414$0$23781$9a566e8b_at_news.aliant.net>
>
> 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.
Date: Wed, 05 Aug 2009 11:15:40 -0300
Message-ID: <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. Received on Wed Aug 05 2009 - 16:15:40 CEST