Re: Guessing?
From: paul c <toledobysea_at_ac.ooyah>
Date: Thu, 19 Jun 2008 20:10:42 GMT
Message-ID: <63z6k.38054$gc5.18499_at_pd7urf2no>
>>> "Bob Badour" <bbadour_at_pei.sympatico.ca> wrote in message
>>> news:483ac46d$0$4069$9a566e8b_at_news.aliant.net...
>>>> paul c wrote:
>>>>> Bob Badour wrote:
...
>>> This just does not make sense. Suppose that a Vendor can also be a
>>> Customer since they're both Companies, and suppose that Company 'Philco'
>>> usually supplies 'RG6 connectors,' but occasionally buys them. So then
>>> if you have two relations,
>>> VendorParts {Company, Part},
>>> CustomerParts {Company, Part},
>>> that enumerate the parts that a company supplies and the parts that a
>>> company buys respectively,
>>> the tuple, {Company:'Philco', Part:'RG6 connector'}, can obviously appear
>>> in both relations, so I don't buy the notion 'any tuple satisfies the
>>> predicate of at most one relation.'
>>> ...
Date: Thu, 19 Jun 2008 20:10:42 GMT
Message-ID: <63z6k.38054$gc5.18499_at_pd7urf2no>
Brian Selzer wrote:
> "paul c" <toledobysea_at_ac.ooyah> wrote in message > news:etU_j.167881$rd2.59570_at_pd7urf3no... >> Brian Selzer wrote:
>>> "Bob Badour" <bbadour_at_pei.sympatico.ca> wrote in message
>>> news:483ac46d$0$4069$9a566e8b_at_news.aliant.net...
>>>> paul c wrote:
>>>>> Bob Badour wrote:
...
>>>> With POOD, any tuple satisfies the predicate of at most one relation in >>>> the dbms. Thus, with POOD, the dbms can calculate a unique relation to >>>> which to apply any insert, update or delete with the goal of avoiding >>>> anomalous behaviour. >>>>
>>> This just does not make sense. Suppose that a Vendor can also be a
>>> Customer since they're both Companies, and suppose that Company 'Philco'
>>> usually supplies 'RG6 connectors,' but occasionally buys them. So then
>>> if you have two relations,
>>>
>>> VendorParts {Company, Part},
>>>
>>> CustomerParts {Company, Part},
>>>
>>> that enumerate the parts that a company supplies and the parts that a
>>> company buys respectively,
>>>
>>> the tuple, {Company:'Philco', Part:'RG6 connector'}, can obviously appear
>>> in both relations, so I don't buy the notion 'any tuple satisfies the
>>> predicate of at most one relation.'
>>> ...
>> >> Isn't this a straw man too? (arguing against POOD with an example that >> doesn't follow POOD.) > > I think it does follow POOD, but I think Badour's overstrict interpretation > of POOD is flawed. > >
In that case, why don't you state your interpretation (in less than say 50 words or so I could hope). Received on Thu Jun 19 2008 - 22:10:42 CEST