Re: 1GB Tables as Classes, or Tables as Types, and all that refuted

On Tue, 23 Nov 2004 15:25:22 +0100, "Ja Lar" <jalar_at_nomail.com> wrote:

>> Indeed, the first statement is not clear for many people but
>> type=variable is an evident blunder for anybody who knows what type
>> and variable are.
>
>If you say so.

You only have to compare both definitions.

>> >Try again: _Why_ is it a great blunder to "mix types with values"? The
>> >answer "that's obvious" is of no (logical) value - that's the hole point
>in
>> >the paper this thread discusses.
>>
>> If you don't know what types, variables and values are, that is your
>> problem.
>
>You are not very helpful: If I don't know the answer to my question, I
>shouldn't ask it?

You know the answer: because they are fundamentally different.

What you don't know is what types and variables really are, and that's why you don't see the obvious differences.

I recomend you Date's $$$ article called "On Logical Differences" or something similar. 72 pages 10$.

And yes you can ask what types, variables and values are.

Type: AKA abstract data type:

http://www.nist.gov/dads/HTML/abstractDataType.html

Variable: a holder or a container for a value. The value placed in variable may change over the time. To say a variable holds a value means that an encoded representation of a value is contained in the variable.

Value: an individual constant, any particular determination. Values have no location in time or space.

Determination: The ascertaining or fixing of the quantity, quality, position, or character of something: a determination of the ship's longitude; a determination of the mass of the universe.

http://dictionary.reference.com/search?q=determination

BTW, thanks to you I have a better definition of value than I had :)

A value is a determination.

>Once again: On one hand you say that it is a great blunder to "map a class
>to a relvar" , and on the other hand you say that it is not a great blunder
>to "map a list of values to a relation". Why?

Once again: because a list of values is a value and a relation is a value. Both are objects (not in the OO sense) of the same kind. And because types and variables are fundamentally different: variables are updateable, types aren't, variables do have location in time and space, classes don't.

>And once again: Why and how can an atrribute of a relation have another
>relation as its domain without thus mixing type with values? (type =
>domain)?

An attribute of a relation can not have another relation as its domain. This is an absurd.

>Btw, the original topic of this thread is not whether there is one or two
>great blunders or not, but if Mr. Gittens arguments against D&D's
>conclusions are valid, ie. that they give no logical foundation for the
>conclusion about 1GB and 2GB.

Gittens is wrong because the conclusion is perfectly founded: the definition of type does not match with the definitions of variable and value, and the definition of relational domain matches perfectly with the definition of type, they are the same thing with two different names, they are synonyms like reply and response.

Regards Received on Wed Nov 24 2004 - 02:19:39 CET