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Re: Microsoft and the two great blunders

From: Costin Cozianu <c_cozianu_at_hotmail.com>
Date: Sun, 28 Dec 2003 13:58:25 -0800
Message-ID: <bsnjnj$er8qp$1@ID-152540.news.uni-berlin.de>


Alfredo Novoa wrote:
> Costin Cozianu <c_cozianu_at_hotmail.com> wrote in message news:<bsgq38$cmb87$1_at_ID-152540.news.uni-berlin.de>...
>
>
>>They don't say give me a relation of customers either.
>
>
> Here they do all the time.
>
>
>>>But my main complaint is about using a single word for table value and
>>>table variable. They are fundamentally different concepts.
>>>
>>
>>Who's using that ?
>
>
> Everybody who use the term.
>
>
>>>Table is more appropiate for the SQL bags, and relation is more
>>>appropiate if you are talking about a relational database.
>>>
>>
>>Ahem, you mean relvar ?
>
>
> No, relation is the short for relation value and relvar is the short
> for relation variable.
>

Well, we were talking about table and table is a shortcut for relvar.

>
>>>I have never seen a table containing all the values of a tuple type at
>>>practice. In many cases it would be physically impossible.
>>>
>>
>>All the values in the domain of interest that are of a certain type. For
>>example all the value of Employee type.
>
>
> The number of values of the Employee type is virtually infinite!
>

Yes, but the one that do apply is typically finite. Plus what's the problem in opearting over infinite value ? Some folks are doing it regularly.

>
>>>It does not have relationship with the great blunder.
>>
>>Oh, but that is allegedly one of the great blunder. Read TTM appendix.
>
>
> No, you are misunderstanding it.
>

Misunderstanding black on white ?

>
>>>Any operator may be a part of several types, and you can express that
>>>without problems with that template (and flawed) grammar.
>>>
>>
>>So if an operator is part of several types, you've got a problem. Are
>>operators part of the type definiton or not ?
>
>
> You are mixing apples with oranges. The proper question should be: Are
> operators definitions part of type definition?

There's two concepts typically: the definition and the declaration. If any, operator declaration should be part of type declaration, to preserve some very important principle of mathematica notation :

  *locality of reasoning*

There are also other principles and concerns like modularity and compositionality that are as clear as mud with D&D proposal.

> And IMO the answer is
> yes.
>

The answer is no, not really.

> But one operator may be shared by several types.
>

Where shared means ??

>
>>>>TYPE ELLIPSE
>>>> IS PLANE_FIGURE
>>>> POSSREP { A LENGTH, B LENGTH, CTR POINT };
>>>
>>>
>>>It is not a complete type definition.
>>>
>>
>>So what would be the complete type definition ?
>
>
> The operators definitions are missing.
>
>
>>Oh. But
>>
>>type Plane_Figure union;
>>
>>Is void of content.
>
>
> Because we have not added the operators definitions.
>
>

And the way to add that is ... ?

>>A proper abstract data type is something entirely
>>different
>
>
> I meant it is similar to an "abstract class".
>

Except it isn't similar to an abstract class.

>
>>What *is* Plane_Figure , and what's the purpose of that declaration ?
>
>
> A union type. A supertype for all plane figure types. It does not have
> a representation, but it may have operators. It may resemble to a Java
> "interface".
>

A union type and a supertype are very different things. That's why a reading in basic type theory may help..

>
>>IMHO your knowledge of the entire subject of type theory is weak.
>
> Surely, but we are talking about very fundamental things. I don't need
> to master type theory in order to know that types are not variables.
>

Nobody said that types were variables. But the very fundamental things you want to talk about, you don't grasp. Like the relationship between types and operators

>
>>>>Nobody is confusing anything.
>>>
>>>Then we live in different worlds.
>>>
>>>Have you readed this:
>>>
>>>http://www.ambysoft.com/persistenceLayer.pdf
>>>
>>>It is the inspiration of dozens of SourceForge and comercial projects.
>>
>>So what ? People are free to waste their time however they wish.
>
>
> So many people hardly can be more confused and misleaded. But of
> course they are very free to waste their time and the resources of
> their employers.
>

And you'd like people to waste resources on Tutorial D, instead ?

That would not be an unreasonable wish, except that people are free to waste their time on whatever they see fit. And if you want to shame them into wasting time on what you think fit, well, you have no proper argument.

>
>>>Entity-types are virtually meaningless. Is the E/R "model" your idea
>>>of a formal framework? }:)
>
>>Yes, it is. A little bit of reading on the subject wouldn't hurt you.
>
> It is hilarious. The E/R model is a well known paradigm of formalism
> lack.
>

Indeed, it is hilarious that you are ignorant and proud of it.

Again, for your own good you might be well advised to buy Thalheim's book. It may as well give you some insights into the relation between database theory and type theory.

And you may get an idea of what formalism might look like.

>
>>>It is clear on the slides.
>>>
>>
>>So you still haven't shown any problem.
>
>
> It was never my intention. I thought that the problems would be very
> clear to the educated readers of the group.
>

Ha, ha, ha. It turns out that the self-appointed educator needs to edcuate himself first.

>
> Regards
> Alfredo

Cheers,
Costin Received on Sun Dec 28 2003 - 15:58:25 CST

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