Re: L

From: paul c <toledobythesea_at_oohay.ac>
Date: Tue, 10 Oct 2006 01:48:18 GMT
Message-ID: <CZCWg.117228$5R2.69131@pd7urf3no>

dawn wrote:

> paul c wrote:
>> dawn wrote:
>>> paul c wrote:
>>>> dawn wrote:
>>>>> paul c wrote:
>>>>>> dawn wrote:
>>>>>>> Hugo Kornelis wrote:

>>>>>>>> On Fri, 06 Oct 2006 23:29:29 GMT, paul c wrote:

>>>>>>>>
>>>>>>>>> Hugo Kornelis wrote:

>>>>>>>> (snip)

>>>>>>>>>> Because relational databases supporting NULL *define* it as a marker
>>>>>>>>>> denoting the absence of a value. Dawn actually makes a good point about
>>>>>>>>>> context: in C for instance, NULL has a completely different meaning.
>>>>>>>>>> ...
>>>>>>>>> Since it has a different meaning in C, there is no point bringing C into
>>>>>>>>> play here.

>>>>>>>> Hi Paul,

>>>>>>>>

>>>>>>>> The point I was trying to make is that NULL has different meaning in
>>>>>>>> different context. Using C as example was a bad choice, since it
>>>>>>>> obfuscated what I was trying to convey, rather than clarifying it.

>>>>>>>>

>>>>>>>> The meaning of NULL in the context of SQL is also quite different from
>>>>>>>> the meaning of NULL in Pick (and possibly other MV databases). That's
>>>>>>>> what I wanted to write, and what I should have written in the first
>>>>>>>> place. Much of the discussion between Cimode and Dawn appears (as I read
>>>>>>>> it) to come from Cimode talking aboout SQL NULL and Dawn talking about
>>>>>>>> Pick NULL - but they both think that the other is discussing the same
>>>>>>>> NULL.

>>>>>>> Thanks for giving your take on that, Hugo, since I was clearly getting
>>>>>>> nowhere.
>>>>>> What else is new.
>>>>>>
>>>>>> You won`t get anywhere as long as you keep comparing apples to oranges,
>>>>>> eg., imagining that Pick has a data model that is comparable to what
>>>>>> Codd had in mind.
>>>>> That is not what this was about, Paul.
>>>> Yes, it is, see below.
>>>>   There are many languages that
>>>>> employ 2VL.  SQL is the odd-ball out.
>>>> You are still talking languages, not r.d. Theory.
>>> I would think you could abstract from that statement.
>>>
>>>> Too bad I can`t quote Codd here.
>>> His approach to NULL is something that many disagree with today, right?
>>>  Think how many hours and dollars the implementation of this approach
>>> to NULL has cost the industry.  Of course one can define NULL this way,
>>> but the costs outweigh the benefits in doing so.  --dawn
>>>
>>>> But just in an effort to get you on a
>>>> more useful track, did SQL endorse Nulls before or after Codd`s 1979
>>>> paper (question mark intended, sorry the keyboard is fine, something to
>>>> do with whatever Mozilla is doing to firefox or thunderbird).
>>
>> Not interested in the editorial.  Would rather you go and find out the
>> answer to my question.
>>
>> p
> 
> In order to get the L out of here (where did that subject name come
> from?), I'll give a guess as I'm not likely to research that right now.
>  [I messed up my ACM membership by signing up for the portal through
> IEEE and lost access to stuff.  I shouldn't do my own admin!]
> 
> My guess is that the SQL NULL was likely in System/R in 1978, but even
> if that is the case, it does not mean it was developed independently of
> Codd.  Was '79 his first publication on the topic?  When did his 4VL
> paper come out?  --dawn
> 

instead of wasting time with admitted guesses, why don`t you just answer the question and say you don`t know and you have no idea why it matters.   your topic seems to be newsgroup rhetoric, not c.d.t.

p Received on Mon Oct 09 2006 - 20:48:18 CDT