Re: Navigation question

"dawn" <dawnwolthuis_at_gmail.com> wrote in message news:1172066290.728188.161780_at_q2g2000cwa.googlegroups.com...
> On Feb 21, 2:01 am, mAsterdam <mAster..._at_vrijdag.org> wrote:
> > dawn wrote:
> > > In another thread "navigation" is again mentioned as undesirable.
> >
> > Navigation is from here to there.
> > Things like distance, direction, movement, traveling time, location,
> > path and space are relevant concepts.
> >
> > In RM the database (at the logical level(*)) is a single-point
> > thing. No navigational term has any meaning in a
> > single point. Conversely, non of the RM terms
> > have any navigational meaning.
>
> Agreed. So, this discussion about navigation is outside of the RM.
>
> > (*) Some may maintain that the RM covers no other level.
> > A lower, physical level is implied, and AFAIK most
> > book that cover RM also touch it. A lot of
> > navigation is going on at that level. Without further
> > qualification, every navigational remark is, by default
> > about that level, the physical level.
> >
> > Nothing good, nothing bad here, just: navigation is something that
> > does not exist within the RM.
>
> Right. I do not know if navigation is often spoken ill of in this
> forum 1) because it is outside of the RM 2) for the same reasons that
> it is outside of the RM, whatever those might be or 3) for other
> reasons. I'm trying to understand what about database navigation is
> considered "bad" and why.
>

You've got it backwards, Dawn.

The defects of user specified navigation were discovered first, and the application of the RM to the problem of alrge shared data banks was developed in order to overcome these defects. Received on Wed Feb 21 2007 - 16:16:28 CET