paul c wrote:
> Alright, here's an old topic, the trans-relational model. (At one time,
> I was intrigued by it, since I don't live in the USA and therefore could
> ignore US patents if I wanted to try to make money off it.) One claim
> for it was that certain run-time sorts or index builds could be
> eliminated, although I seem to remember one of the big names cautioning
> that there might always be a 'preferred order' (sorry if I've mis-quoted
> and I don't mean to be sly, the people who publicized it remain deep
> thinkers in my book). After some study, undoubtedly inferior in parts,
> I concluded that one could accomplish the same 'physical' effect if
> every 'column' were indexed.
>
>
> 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.
>
>
> 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.
>
>
> I don't remember this aspect of that model ever being discussed here but
> I contend it is just as reasonable as Codd's original intent, which was
> in part to make access to data storage more intuitive.
I wonder if part of the issue is the name? As I understand it, the TRM
is a storage level device, operating as a suitable substrata for a fully
relational DBMS to use - but not itself constrained by all the rules of
the RM. For example, it unabashedly has columns in a defined order, not
in an undefined order.
So, it is a possible physical level representation of data that the RM
handles at the logical level with the rules of the RM running the show
at the logical level.
When were the patents on the Trans-Relational Model issued, does anyone
remember? I wonder how much longer before they expire - I expect it is
a decade away before those in the USA can use them unfettered, but it
might be a bit less.
I'm also not clear whether Codd ever really discussed or got involved
with it. C J Date included an appendix in his 8th Edn, and apparently
wrote a book on it but that got stranded when the company ran out of
money and the VCs and founders no longer saw eye-to-eye, or thereabouts.
OK - maybe my new subject for the thread is as misleading as the old.
It is still "Trans-Relational Model Moribundus", but the topic of
discussing it has been revivified.
--
Jonathan Leffler #include <disclaimer.h>
Email: jleffler@[EMAIL PROTECTED]
jleffler@[EMAIL PROTECTED]
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