Re: Sixth normal form
From: paul c <toledobythesea_at_oohay.ac>
Date: Thu, 02 Aug 2007 02:59:05 GMT
Message-ID: <ZLbsi.23504$fJ5.6912_at_pd7urf1no>
>
>
> Are you saying that Codd's use of "key update" in his definitive1970 paper
> was also mumbo-jumbo?
> ...
>
>
> It should be obvious that relational algebra and calculus are meant for
> queries, not updates. Unlike the operators of relational algebra, neither
> insert, update, nor delete returns a result. Nor does relational
> assignment. More importantly, the algebra and the calculus involve a single
> database value (set of relation values), a snapshot of reality if you
> prefer. An update operator (as D&D call them) involves two snapshots of
> reality, and truth in one does not imply truth in the other.
>
> Before you make a complete fool of yourself, I suggest you read Codd's 1990
> book. You should be able to find it online now. I did. I can't remember
> where, though.
> ...
Date: Thu, 02 Aug 2007 02:59:05 GMT
Message-ID: <ZLbsi.23504$fJ5.6912_at_pd7urf1no>
Brian Selzer wrote:
> "paul c" <toledobythesea_at_oohay.ac> wrote in message
> news:xV5si.22613$rX4.14717_at_pd7urf2no...
>
>>Brian Selzer wrote: >>... >> >>>It's somewhat unrelated, ... >> >>I was with you up 'til the first comma in the last paragraph. It sure >>doesn't have to do with redundancy. First there were rigid keys, then >>contingent keys, now we have immune keys. Newcomers please note - don't >>believe this mumbo-jumbo, it is all undefined mysticism, as is the term >>"key update". >>
>
>
> Are you saying that Codd's use of "key update" in his definitive1970 paper
> was also mumbo-jumbo?
> ...
Yes.
> Isn't it strange that people who can't come up with a solid argument resort
> to misrepresentation, nitpicking over terminology, and outright derision.
> Often they end up with their foot in their mouth.
> ...
No, it isn't strange to me, I see it all the time.
>
>>Also, I would like to know if anybody has ever invented a relational >>algebra or calculus that supports "update". AFAIK, update is either a >>system colloquial, environmental or a language, say SQL, term. Yeah, I >>know people say "update" a tuple et cetera and I think that's okay if it >>is agreed and understood just what exactly the system or dbms they have in >>mind is going to do about the "update". In the recent threads, I don't >>and I'm pretty sure we don't either. >>
>
>
> It should be obvious that relational algebra and calculus are meant for
> queries, not updates. Unlike the operators of relational algebra, neither
> insert, update, nor delete returns a result. Nor does relational
> assignment. More importantly, the algebra and the calculus involve a single
> database value (set of relation values), a snapshot of reality if you
> prefer. An update operator (as D&D call them) involves two snapshots of
> reality, and truth in one does not imply truth in the other.
>
> Before you make a complete fool of yourself, I suggest you read Codd's 1990
> book. You should be able to find it online now. I did. I can't remember
> where, though.
> ...
Let me know if you remember. A salesman stole mine.
p Received on Thu Aug 02 2007 - 04:59:05 CEST