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Re: Possible bridges between OO programming proponents and relational model

From: Cimode <cimode_at_hotmail.com>
Date: 3 Jun 2006 14:17:47 -0700
Message-ID: <1149369467.778685.262570@h76g2000cwa.googlegroups.com>


<<I already elaborated. You simply omitted it from your excerpt. >> << I am not certain I agree with that last sentence. Of the dbmses that

have widely or deeply penetrated the market, SQL based systems are the best we have. There may or may not be better alternatives that are relatively unknown. >> I will take that as ellaboration. No disagreement here.

<< Since you removed all context of what I wrote, I no longer have any idea
 what we are discussing.>>
Sorry I am not used to exchange on NG. Do not have the habits and jargons ;) (Excuse the confusion it may have produced)

<<Which is irrelevant, as I already explained.>> I reread your explanation but I am still doubtful about its relevance to the point of this thread. The main point in this thread is to exchange information on a physical standpoint as mainly. You are placing yourself mainly on a logical standpoint on which I do not believe we have a real disagreement.

<<How can you know something when it is false? "As you well know, the sky
 beneath my feet is yellow." Did you know the sky is beneath my feet? Did
you know it was yellow? Is the sky beneath my feet yellow?>>I do not see an relevance in this analogy.

<< I think you will find collaboration here. But the collaborators are not
 in the habit of holding onto nonsensical statements.>> I hope so.

<< Since neither (1,2,3) nor (3,5,5) are points on a sphere of radius 5, I
 highly doubt that they will ever appear in any possible representation

 of the relvar.>>
I am not doing geometry. I reused your example to illustrate that if a specific SQL implementation *physical* representation of a relvar is bidimensional (because its body is only column/row represented) then it is clearly what defeats independence.

<<The infertile ground I referred to is OO not the newsgroup.>>OK. misunderstood.(apologies for that)

<< I never accused you of misusing "degree". You used "dimensions"  nonsensically.>>I used *dimensions* in a mathematical sense. That certainly does not make it nonsense.

<<You have not established that at all.>> This is not formal theory formulation. I am trying primarily to exchange through a difficult media/ Doing the best I can .(know that I have been educating myself on Relational concepts based on *translations* from DATE, PASCAL, DARWEN which does not make it easy to exchange with English speaking audiences). I do not understand how such simple concepts are so troublesome to you.

<<Why would I think a linear address space has more than one dimension?
>>

Why do you keep making me say what I do not say. I have never said that. in memory are not one dimensional only.

<<Why would you think the linearity of the address space says anything  about the dimensionality of an SQL table?>> I have not said nor implied that. I am suggesting that the bidimensional (in a mathematical sense) aspect of a physical adressing scheme may be one of the cause for the lack of independence between logical and physical layer in current SQL DBMS.

Thank you for your insight.

Bob Badour wrote:
> Cimode wrote:
>
> > <<I am not certain I agree with that last sentence.>>Can you ellaborate
> > on that? What
> > do you have in mind?
>
> I already elaborated. You simply omitted it from your excerpt.
>
>
> > <<That's a different issue.>>You really think so? I would argue that
> > it is too closely related to to be ignored.
>
> Since you removed all context of what I wrote, I no longer have any idea
> what we are discussing.
>
>
> > <<However, that does not change the degree of a table and
> > does not change the fact that the degree is a direct measure of the
> > dimensions.>> Yes. So. I have never denied that. This is why I
> > made a distinction between SQL tables as they are implemented and SQL
> > tables as they should be represented.
>
> Which is irrelevant, as I already explained.
>
>
> > <<Regardless of implementation, a sphere of radius 5 has three
> > dimensions
> > as does the set of integral points on a sphere of radius 5. The table
> > s5
> > above has degree three and three dimensions: x, y and z.>>
> > Yes. That's not the point.
>
> If you are trying to make a different point, I suggest you use words
> that mean something else, then.
>
>
> > <<As a matter of fact, I do not know that because it is in fact not
> > true.>>
> > I don't understand this statement. How can you not know something and
> > disqualify it as not being true. Could you ellaborate?
>

<<How can you know something when it is false? "As you well know, the sky
 beneath my feet is yellow." Did you know the sky is beneath my feet? Did
you know it was yellow? Is the sky beneath my feet yellow?>>
>
>
> > <<I think you will find far more fertile ground elsewhere.>>Probably.
> > Looking at the spirit of most comments I have read in other threads NG,
> > it seems collaboration is not the main overall drive in this NG. Thank
> > you for pointing it out.
>
> I think you will find collaboration here. But the collaborators are not
> in the habit of holding onto nonsensical statements.
>
> The infertile ground I referred to is OO not the newsgroup.
>
>
> > << When you write that an SQL table of degree 3 has two dimensions,
> > then
> > what you write is nonsense regardless of your belief.>>
> >
> > I have not written that anywhere (have not used degree). I am curious
> > however as to *what* exactly makes you believe that I said that.
>
> I never accused you of misusing "degree". You used "dimensions"
> nonsensically.
>
>
> > If you don't mind, I will use your example to clarify:
> >
> > ...Consider the following relvar
> >
> > T5: x,y,z
> >
> > ...then consider its SQL counterpart...
> >
> > create table s5 (
> > x as integer not null
> > , y as integer not null
> > , z as integer not null
> > ) primary key (x,y,z)
> >
> > ...then consider the following view
> >
> > select x, y, z from s5
> >
> > ...my point is that the following possible output in one possible
> > representation of the relvar...
> >
> > 1, 2, 3
> > 3, 5, 5
>
> Since neither (1,2,3) nor (3,5,5) are points on a sphere of radius 5, I
> highly doubt that they will ever appear in any possible representation
> of the relvar.
>
>
> > ..considering this output is a direct disk image implementation meaning
> > disk storage mechanism and in-memory representation in current SQL DBMS
> > are *physically* storing
>
> You have not established that at all.
>
>
> > Adress 1/ 1, 2, 3
> > Adress 2/ 3, 5, 5
>
> Again, this is not necessarily the case--not even for SQL as currently
> implemented by most vendors.
>
>
> > I do not understand why you advocate the idea that this particular
> > physical implementation is anything else than bidimensional?
>
> Why would I think a linear address space has more than one dimension?
> Why would you think the linearity of the address space says anything
> about the dimensionality of an SQL table?
Received on Sat Jun 03 2006 - 16:17:47 CDT

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