Re: Something new for the New Year (2008).

On Jan 4, 3:49 am, Rob <rmpsf..._at_gmail.com> wrote:
> Wow, I sure stirred up a hornets nest.
>
> Let me see if I can make a few observations and then back away from
> this. The USPTO delivered a particularly inspiring Office Action and
> my first responsibility must be to respond to them, not to cdt.
>
> 1. Rob said the following:
>
> > Some (like JOG) interpret the data structures (relations) of a
> > relational database as sets of "true" logical statements.
>
> In reply, JOG said:
>
> >>I'm sorry Rob, but that's not an interpretation. Thats /what it is/.
> >>The relations of a relational database encode true facts about the
> >>world.
>
> But according to Marshall:
>
> >as far as the RM goes, it models our
> >ideas about real-world entities and our ideas about real-world
> >relationships in exactly the same way: as mathematical relations.
>

There is no difference between my and Marshall's views, because they are just a repetition of what Codd defined the relational model to be.

> So as long as there is no universal consensus about how
> relational databases and the relational model allow us to represent

But there /is/ universal consensus from people who have read the RM paper. A tuple represents a fact as an instantiation of a predicate. There is much discussion concerning other factors of the RM, but how it represent facts is certainly not a point of contention.

> "true facts" and "entities and ... relationships", I think I should be
> allowed to have my primitive view of a relational database as a
> set of sets of vectors. (Please, hold your applause until the end.)
>[snip]

I wonder if you are perhaps you trying to implement a different data model inside of the RM mechanism (as people do with EAV)? The PKFK and JT "structures" you describe correspond directly to propositions that are stated in the real world, but I am at a loss as to what facts your more complex A-L "structure" correspond to. Received on Fri Jan 04 2008 - 19:23:27 CET