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Re: Possible bridges between OO programming proponents and relational model

From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Sun, 04 Jun 2006 19:13:36 GMT
Message-ID: <AhGgg.17481$A26.406047@ursa-nb00s0.nbnet.nb.ca>


Cimode wrote:

> Alfredo Novoa,
> Cimode ha escrito:
>

>>><< This does not make any sense, the dimension of a relvar is the
>>>number
>>> of attributes.>>Absolutely.  but SQL table implementations are not
>>>relvar, just a possible representation of a relvar.
>>
>>This does not make any sense.

>
> It does not make any sense because you are confusing R-Table/SQL table
> and their punctual in-memory representation at runtime.
>
> //A SQL table with three attributes is always three dimensional
> independently of how it is implemented.//
>
> At logical level yes but not at physical level.

At any level, Cimode. If you don't mean to refer to the SQL table, then refer to something else that you do mean. Any triplet, though, represents three dimensions.

Are you referring to a two-dimensional array representing the table? Are you referring to something else?

> You advance a strong argument without anything to back it up Prove it.
> What is the in-memory representation of a SQL table at run time?

Anything one wants that represents the SQL table. It might depend on the indexes used. It might depend on how one distributes the table. It might never get represented exactly as a table at all.

[snip]

Several people have already understood the issue
> here but you are not one of them.

You advance a strong argument without anything to back it up. Prove it.

> //<<I suppose that you know how to represent a cube with a table.>> It
> is
> an analogy used for communication's sake. You misread and
> misunderstood my comment. I said that a face of a cube is
> bidimensional and is a comparable to what a SQL Table is to a relvar.

And any representation of a face of a cube is bidimensional. However, any representation of the cube is three dimensional, or it no longer represents a cube. Don't confuse the projection of a cube with a cube.

> //Your comparation is completely nonsensical.// This is getting
> boring.
>
> Are you suggesting that the memory is less physical than the
>

>>>disk?>>Interesting question but the answer is obviously no.
>>
>>Indeed but your previous post seems to suggest the contrary.

>
> The
> argument here is about getting better independence *progressively*
> through thinking as to how in-memory representation of relvar could be
> more truthful to what a relvar .

You have already stated that. However, you then immediately confused the logical and the physical again.

Any in-memory representation of a relvar that represents a relvar is truthful to what a relvar is. Otherwise, it doesn't represent a relvar. Similarly, any in-memory representation of an SQL table that represents an SQL table is truthful to what an SQL table is. Otherwise, it doesn't represent an SQL table.

What in-memory representation do you want to discuss? A row store? A column store? Some other representation? Others have offered you alternative vocabulary for what they think you might mean, but you totally ignored it every time.

> //Another completely incoherent paragraph.//
> This is getting repetitive but I should clarify that...Do you deny that
> the body of a relvar represented after a select x, y, z is ran is
> anything else similar to
>
> X-AXIS----------------
> Y-AXIS 1,2,3
> - 2,4,4
> - 4,4,4
> - 5,5,8
>
> Do you deny that X and Y represent mathematical dimensions?

But the dimensions of what? A piece of paper? A computer monitor? That is the point that seems to elude you. Neither X nor Y are properties of the relvar or of the implementation of the relvar.

The body of the relvar remains unaltered by the select as does the implementation of the relvar.

> Do you support that the above representation is the relvar itself.

No, it isn't the relvar itself. It is a representation of a relation on my computer monitor (when I look at it.) X and Y are dimensions of my computer monitor.

   If
> you answered yes to any of the above questions then you are wrong dead
> wrong.
>
> // The answer is evident to me: OO has nothing to offer. Both things
> are
> completely unrelated.//
> Prove it. If your knowledge of OO mechanisms is as effective as the
> confusions you are making between logical and physical layers,

Alfredo has shown no indication whatsoever of confusing anything. If your only goal is to insult the people who are trying to help you, you can go fuck yourself. Received on Sun Jun 04 2006 - 14:13:36 CDT

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