Re: MV Keys

I just want to clarify: I think that a string is a scalar if ALL of the following statements hold, not ANY. Sorry for the confusion.

"Brian Selzer" <brian_at_selzer-software.com> wrote in message news:GHgNf.26120$_S7.24277_at_newssvr14.news.prodigy.com...
>
> "Jon Heggland" <heggland_at_idi.ntnu.no> wrote in message
> news:MPG.1e6fa30f17a25f9598976d_at_news.ntnu.no...
>> In article <3bla025sc4m8u59a7qoc09bipjtnh5tmuk_at_4ax.com>,
>> invalid_at_bigfoot.com says...
>>> I don't agree with this. Strings are (IMHO) scalar types because they
>>> can be sorted.
>>
>> Anything can be sorted. You just have to define an order. The order of
>> strings is essentially arbitrary, and you can sort lists of characters
>> the same way you sort strings.
>>
>>> However, mathematical operations on them, except for
>>> comparison operators, are not possible. But there are other
>>> operations, such as concatenation and substring, which are.
>>
>> What is a mathematical operation, and why are they important in this
>> context? Any list can support concatenation and "subbing"---what point
>> are you trying to make?
>>
>>> Also, the characters by themselves are meaningless much as the bits in
>>> a number by themselves are meaningless. It is the order of the bits,
>>> and the order of the characters, that give the number or string any
>>> meaning. Therefore, if you consider VARCHAR to be a compound type, you
>>> would have to say that DECIMAL is, too. And with real compound types
>>> such as lists or arrays, it is the elements themselves, and not the
>>> collection of elements, which gives the type semantic meaning.
>>
>> I'd say the meaning is primarily in the mind of the human using the
>> system. But I agree(?) that DECIMAL may indeed be considered compound. I
>> can use an int32 as an array of bits, each bit with a "meaning" in
>> itself---and I can likewise use a string as an array of characters. It
>> is just a matter of perspective, of mindset. The computer can't tell the
>> difference.
>>
>>> But I'm not a mathematician, so I couldn't say what it takes to prove
>>> whether something is a scalar type or not. Is there a formal
>>> definition?
>>
>> Exactly my question. I don't think there can be, but I may be wrong. :)
>
> Doesn't the determination of whether a type is scalar or not depend upon
> the universe of discourse? I think that a string is a scalar if any of
> the following statements hold: (1) individual character values don't
> belong to the universe of discourse, (2) the meaning of the individual
> character values aren't directly augmented by the attribute name, (3) the
> meaning of the individual character values aren't augmented by their
> position in the list, or (4) it is only the permutation of character
> values that has meaning with respect to the containing relation. For
> example, the elements in a list of birth dates aren't just dates, they're
> birth dates; the numbers in a coordinate aren't just numbers, they're
> longitude and lattitude. I think that some of those properties could be
> applied to other types as well, though I can't think of an example just
> now.
>
>> --
>> Jon
>
>
Received on Wed Mar 01 2006 - 13:51:15 CET