Re: Microsoft and the two great blunders
Date: Sun, 28 Dec 2003 13:58:25 -0800
Message-ID: <bsnjnj$er8qp$1_at_ID-152540.news.uni-berlin.de>
Alfredo Novoa wrote:
> Costin Cozianu <c_cozianu_at_hotmail.com> wrote in message news:<bsgq38$cmb87$1@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!
>
>
>>>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*
> 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 ?
>
>>>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.
>
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 - 22:58:25 CET