Re: The Practical Benefits of the Relational Model
From: Leandro Guimarães Faria Corsetti Dutra <lgcdutra_at_terra.com.br>
Date: Mon, 04 Nov 2002 15:14:34 +0100
Message-ID: <aq5vc9$6trji$2_at_ID-148886.news.dfncis.de>
>
> Yes, yes. Note the word 'presumably' and the words 'just as easily'
>
> No. The point is that Chris & David are not saying that. The user is
> simply wanting to add a new proposition to the database, but without
> 'Orthogonal Design', the DBMS cannot always know what to do with the
> new proposition, because some meaning is hidden.
>
> If so, how do you propose to 'make known to both system and other
> users' such constraints?
Date: Mon, 04 Nov 2002 15:14:34 +0100
Message-ID: <aq5vc9$6trji$2_at_ID-148886.news.dfncis.de>
Paul Vernon wrote:
> "Leandro Guimarães Faria Corsetti Dutra" wrote in message
> news:aq5dh5$6il6e$1_at_ID-148886.news.dfncis.de...
>
>> Paul Vernon wrote: >> >>> "Now suppose the row is to be inserted into this database." >> >> Now read the following phrases and the next paragraph or two.
>
> Yes, yes. Note the word 'presumably' and the words 'just as easily'
And?…
>> You can now understand that the row is indeed to be inserted not >> simply into the database, but into a specific relation.
>
> No. The point is that Chris & David are not saying that. The user is
> simply wanting to add a new proposition to the database, but without
> 'Orthogonal Design', the DBMS cannot always know what to do with the
> new proposition, because some meaning is hidden.
Hm. That's not what I understood. Perhaps I'm reading too much, but I think not.
What I did read is that the DBMS should be able to reject specific updates based on some kind of representation of external rules, and those are constraints.
>> It is just a matter of how to make known to both system and other >> users the constraints that would give meaning to the relations >> apart from simple meaning, thus avoiding incorrect data entry.
>
> If so, how do you propose to 'make known to both system and other
> users' such constraints?
Still waiting for the second part of the article!
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