Re: TRM and sorts

On 5 sep, 04:22, paul c <toledobythe..._at_oohay.ac> wrote:
> I wonder if anybody here has spent much time thinking about the
> practicalities of the "trans-relational model"?
I did. throughouly. I have implemented an assembly disk only db core supporting basic domain operations (union, intersection, division) with select and insert's (*not* in the traditional sql sense)

> I can see its value for joins that don't involve projections of
> relations that have a great many attributes, however it seems to assume
> that all "tables" are pre-sorted
Not exactly. In TRM, only physical data layer is sorted in several orders and because TRM does make a clean separation between data and physical layers, *tables* (or R-tables) are not in the physical layer aymore.

> (which for some apps I think is a
> reasonable assumption) and since "ORDERing" often involves permutations
> of attributes, I think that any implementation that supports ordering on
> multiple attributes must either pre-sort every permutation of attributes
> or implement the equivalent of a run-time sort.
paul,

TRM is the closest possible implementation of what might be an independence between physical and logical layers. in TRM, the predetermined *physical* pre-order of data serves the purpose of allowing a nondeterministic logical odering of a specific R-Table (I apologize, I just do not like using the term table). R-Tables are run time built and their order is determined only through memory adresses permutations. Therefore, one could say that the main advantage of the computing model is that *logical* representation of data is indeed sorted in several orders *almost* simultaneously.

> Sometimes I wonder if this is one reason why it might be thought
> deficient. I'm curious as to what others here might condider practical
> deficiencies.
Quite frankly I do not think order is a major drawback that could make TRM deficient . From the experience I had in the last years, the main drawback I have found is that it requires more mathematical tools to support some undefined areas of TRM where basic computing operations (permutations and combinations) are not sufficient anymore to implement relational algebra concepts. For instance, at the moment I am considering using vectorial mahematical tools to support the implementation of run time domains.

Froe the results I have obtained, I can tell that TRM is the closest computing model we have to what maybe some day a relational system but that it requires much more time and effort to do the necessay math to improve it. I believe the hastiness of Tarin to exploit it commercially due to its obvious supriority over traditional direct image is what caused its initial failure. IMHO.
> p
Received on Sat Sep 08 2007 - 01:29:00 CEST