Re: Possible bridges between OO programming proponents and relational model

Thank you for your feedback.

<< 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. Commonly
implemented SQL DBMS Tables are bidimensional.

<< The only way to do this is to force all logical tables to have two
attributes.>>Why is that? What sources makes you believe that?
(Curious about that assertion) Are you refering to Transrelational
Model?

<<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.
(the relvar being a 3 dimensional relvar). This analogy has been used
by DATE and PASCAL and I find it very valid.

<<Are you suggesting that the memory is less physical than the
disk?>>Interesting question but the answer is obviously no. 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 . The question is whether OO in-memory
mechanisms could support such effort. And how?

Alfredo Novoa wrote:
Cimode ha escrito:

One of the main current flaws of current SQL DBMS systems is their
incapability to implement the multidimensionality of relvars.

This does not make any sense, the dimension of a relvar is the number
of attributes.

The main
reason seems to be the lack of independence between the physical layer
and logical layer the represent the data. In several DBMS tuples are
right away on disk projections imposing that all tables are considered
bidimensional.

The only way to do this is to force all logical tables to have two
attributes.

In fact, it should not be the case because a
bidimensional RTable is only a *representation* of some entity. An
interesting analogy that may help communication, is Rubi's Cube (3
dimensional): looking at one face of the cube it's only one possible
representation of the cube (being the relvar)

I suppose that you know how to represent a cube with a table.

some insight (flamers please refrain) onto how OO mechanism may help
separate the logical operation (in memory) from physical layer...

Are you suggesting that the memory is less physical than the disk?


Regards
Alfredo

.

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