Re: Principle of Orthogonal Design

On Jan 8, 6:51 pm, JOG <j..._at_cs.nott.ac.uk> wrote:
> I was wondering what your current stances towards the principle of
> current design is cdt - info about the POOD is actually pretty sparse
> on google, which has not helped my own understanding. I gather that
> Date has realigned his opinion - although what to I know not - and
> that Darwen rejected the original POOD paper outright given that
> McGovern posits that:
>
> R1 { X INTEGER, Y INTEGER }
> R2 { A INTEGER, B INTEGER }
>
> violates the principle, whatever the relations' attribute names.
> Instinctively it does seem rather odd that a predicates such as:
>
> * on Day:X the shop had noCustomers:Y
> * on Roll:A, the dice showed the Number:B
>
> cannot share the same database. Have I interpreted the debate
> correctly? Any insights or corrections are, as ever, appreciated -
> POOD is certainly thought provoking, and the concept that an update
> need not require specifcation of a table name is an interesting one.

I'm sure you've run across this exchange (since it seems to be the source of the example cited), but: http://www.dbdebunk.com/page/page/3010532.htm

From Pascal, addressing McGovern: "It is quite possible that the difference between you and CJD stems from the difference between his header/body view of a relation, which you (and recently me) do not espouse, and therefore differing definitions of a tuple."

Regarding the example you gave above, it seems the disagreement may be stemming, as you indicate, from a confusion over whether the types for the relations' attributes are declared from a syntactic domain or from a semantic domain. The example looks, to me, like the former. I would expect if it were the latter, domain names would more closely reflect that.

TroyK Received on Wed Jan 09 2008 - 21:37:12 CET