Re: Why are [Database] Mathematicians Crippled ?

Jan

> On Tuesday, 3 February 2015 05:54:27 UTC+11, Jan Hidders wrote:
> Op maandag 2 februari 2015 16:53:05 UTC+1 schreef Derek Asirvadem:
> > > On Tuesday, 3 February 2015 02:10:09 UTC+11, Jan Hidders wrote:
> > >
> > > A correction: upon rematching the video I saw that he actually does give the definition in the beginning, even if somewhat briefly. He also refers to the lecture notes and mentions that they contain the full definition. So I withdraw my criticism.
> >
> > Ok.
> >
> > We are progressing very slowly.
> >
> > Now I realise, you probably did not understand my first post about this video.
> >
> > I know that he inflates the value of his knowledge, whatever he is going to teach, by mentioning databases that are in 1NF. I know that he gives the well-known theoretical "definition" for what is suggested as 3NF. But what you do not know is, that definition is the usual, stupid, fractured, fragmented, definition that is only relevant to theoreticians.
> >
> > It is only a fraction of the original Codd definition.
>
> Interesting. So what is his definition of 3NF and how does it differ from Codd's? Is it just different in wording, or is it actually not equivalent?

That is difficult to express in your terms, because that process began just recently, and progress is slow, because there is no dictionary. And because the English doesn't work for you (I am sure that it is not a translation problem). Let me try anyway.

1. So you have the Codd definition, right ? Predates the donkey by decades; well-understood and accepted in the physical universe, etc. The 99%. Again, the unchanging law is, since you are not aware of it, since 1971, Codd's definition of Third Normal Form. ____ "Every non-key attribute is Functionally Dependent on the Key, the whole Key, and nothing but the Key"
2. You have the nutty professor, who gives: "<trigger fear response> <trigger self-importance> <trigger future security> Given a relation R{x-instance, y-instance} if they (whatever "they" means) agree on the x-attributes, then they /must/ agree on the y-attributes if that is the case then we say x functionally determines y"

Do I have that correct ?

Good.

3. So, using all your powers as a human, do you perceive any difference between [1] and [2] ?

If you do NOT see a difference, then you are operating at a sub-human level, and there is no point is the two of us wasting any further time. Please do not continue with this post.

If you DO see a difference, then good, continue with this post.

4. FYI, I perceive many differences. But before I enumerate them, there is a sticking point in my head, so let me get it out os the way, then I will continue.

5. Now I understand that the donkey means to transmit the well-known theoretical "definition", that the one percent know. By the Grace of God, when I know someone is intending to do something Q, and he does something less than his intent Q-p, my humanity, my mind kicks in, and fills the gap, in order to continue, without stopping the process and getting the pig to fix the difference (Q-p - Q), before carrying on. Except when the person is giving something from a position of authority. Donkey is teaching, that is a position of authority. We should stop the video there, at that point, and go home.

6. But because you and I appear to be more capable than the jungle bunny, I go past that, and my mind fills in the blanks. Once that is done, I cannot go back to the monkey's "definition" of the theoretical "definition". My intent is to continue with you. I know the theoretical "definition", which is:

____Given a relation R{x,y}
____if x->y then y is functionally dependent on x
____and not otherwise.

7. So, using all your powers as a human, do you perceive any difference between [1] and [6] ?

If you do NOT see a difference, then you are operating at a sub-human level, and there is no point is the two of us wasting any further time. Please do not continue with this post.

If you DO see a difference, then good, continue with this post.

8. What is the difference, you ask me. Enumeration of differences. Between the definition and the theoretical "definition", of Functional Dependency. Because there are substantial differences, the theoretical "definition" is in fact, a non-definition. Not exhaustive:

a the difference is partly the wording, which is vastly different --- the difference is not merely wording, it is much more than that

b the non-definition is missing both concepts, and imperatives that are contained in the definition

c the definition gives the concept of the KEY --- the non-definition is missing the concept of the KEY

d the definition gives that one must have a KEY in order for an attribute to have something that it is, or is not, functionally dependent upon --- the non-definition is absent that restriction

e the definition gives that in the event that there is a KEY, then the attribute must be functionally dependent on the KEY --- the non-definition, since it does not have restriction (d) allows dependencies (we can't call it Functional Dependency, because that is defined) on non-key attributes

f the definition gives that if there is no KEY, there is nothing for the attribute to be functionally dependent upon --- the definition gives that in that case, there are no functional dependencies --- the non-definition, since it does not have restriction (d), since it allows violation of (e), allows dependencies where the definition prohibits it

g the definition gives the concept of the COMPOUND KEY, made up of more-than-one attribute --- the non-definition is missing the concept of the COMPOUND KEY

h the definition gives that in the event that one has a COMPOUND KEY, then the attribute must be functionally dependent on the WHOLE COMPOUND KEY, and not part of the COMPOUND KEY --- the definition gives that in any other case, there are no functional dependencies --- the non-definition is missing that imperative, and its corollary, it allows dependencies on parts of a COMPOUND KEY

i the definition prohibits dependencies of attributes upon non-key attributes --- the non-definition expressly permits dependencies of attributes upon non-key attributes --- the non-definition permits violations of the definition

The differences are substantial, material, and too many to suggest that they are even comparable. I have not listed each violation, I have listed just one, I trust I have given enough specific information, such that you can figure that out for yourself. Since the non-definition expressly permits conditions that the definition expressly prohibits, the non-definition is a violation of the definition.

The non-definition is totally null and void.

> > It is only a fraction of the original Codd definition.

Proved.

Now, stop arguing, non-defining, re-defining, and find something productive work to do employ your life force.

> > I don't have to do any such thing, I have already explained why. The law stands for forty five years. This freak (or some freak who wrote the harry potter novel that he is using, came after that. So it is his job, the authors job, not my job, to explain why the freak is teaching something that goes against the law.

> Indeed it is, if that is what he was doing. But that you have not demonstrated yet.

I have now.

> That should be fairly easy to do. You claimed that his use of the term functional dependency is non-standard. So all you have to do is point to a particular statement that he made in his lecture about functional dependencies that is not consistent with the standard definition.

I have done that now.

Good night
Cheers
Derek Received on Tue Feb 03 2015 - 14:46:12 CET