Re: Sigh... the evil that google does...

On 11 mai, 01:02, paul c <toledoby..._at_ac.ooyah> wrote: Hi paul,
[Snipped]
> I concluded that one could accomplish the same 'physical' effect if
> every 'column' were indexed.
 Yes.

> However, in certain cases, it seemed to me that even if Codd was
> approving of it (or so I remember reading), it denied his goal of
> 'symmetric exploitation', reason being that it depended on projections
> of columns that were 'adjacent' (my term) in the 'zig-zag' organization
> of physical columns, eg., if the zigzag connected column a to b and b to
> c but the query involved only columns a and c, then the result wouldn't
> have what I think of as a 'pleasing' order, unless a sort were invoked.
Tarin failed to deal with solving the mathematical counterpart of zig zags. He failed to minimize mathematically the number of operations necessary to reconstitute the tuple. He thought that separating the layers should de facto be *sufficient* but he failed to see that it was just *necessary*. I have proved mathematically that a storing system that imposes *any* kind of ordering to represent a binary relation necessarily has an equally increasing of operations to reconstitute tuples as more un-ary domains intersect with domain defined by the set of all tuples. That fundamental problem defeats in fact the entire purpose of data independence.

Based on the study of Tarin's work and then mistakes, I have expanded to try to avoid transrelational model shortcomings by designing a radically different appoach to how relation can be reconstituted at run time.

> I realize that a pleasing order is counter to relational dogma but when
> it comes to the mundane domains such as dollars and dates that I've been
> indoctrinated in all my life, I find ordering of those familiar domains
> to be just as powerful, helpful and convenient as pretty much any logic
> I'm aware of. As far as I can tell, Codd's symmetric exploitation could
> be achieved if every permutation of 'columns' were encoded in the
> trans-relational intermediate layer.

Permutation are logical operations that are in fact not efficient as far as number of operations involved to reconstitute relation domain elements. Among other things, symmetric exploitation is impossible when any binary relation is encoded as is on the physical disk.

I have created a method that we can name relation reduction that allows to minimize operations at elementary level. The method is based on the study of the relationship between the cardinality of each attribute domain element and relation domain tuple. I also designed a subsequent new physical encoding scheme far more efficient than any encoding scheme involving a direct encoding. I do not want to discredit Tarin's work because it is probable that I would have never thought about that without studying TRM and seeing where it fails but I can say with certainty that TRM is *still* a direct image system.

The relation reduction does not put in fact put *any* ordering as a prerequisite onto encoding information onto the physical layer which brings it in coherence with the logical layer while keeping both layers separate. The consequences are numerous and express true data independence:

The larger is the tuple set the more efficient the encoding. I can actually see sometime file sizes *decrease* when the number of tuples to be represented increases: the more logical information is encoded the smaller the physical counterpart of that information. I believe this is true data independence.

I must give a strong credit to Tarin's work as it was innovative enough to trigger new questions which led me here.

[Snipped] Received on Thu May 15 2008 - 01:44:02 CEST