Re: Navigation question

On Mar 2, 4:29 pm, "Walt" <wami..._at_verizon.net> wrote:
> <d..._at_tincat-group.com> wrote in message
>
> news:1172783481.330298.311380_at_t69g2000cwt.googlegroups.com...
>
>
>
> > On Mar 1, 8:43 am, "Walt" <wami..._at_verizon.net> wrote:
> > > "dawn" <dawnwolth..._at_gmail.com> wrote in message
>
> > >news:1172707120.938940.196760_at_t69g2000cwt.googlegroups.com...
>
> > > > > Who clumps it in with physical navigation?
>
> > > > The Third-Generation Database System Manifesto that I referred to
> > > > earlier is one such.
>
> > > I did a quick scan of this document, and found no references to "logical
> > > navigation".
>
> > No, I don't know if anyone uses that phrase except for me. It speaks
> > only against navigation and I'm trying to figure out if it is only
> > opposed to physical navigation rather than all database navigation.
> > It was referred to in another document (ppt) I downloaded as a place
> > to find information on why navigation is bad.
>
> > > There were many references to "physical navigation", and
> > > several references to "navigation" in general, but no references to
> > > "logical navigation".
>
> > That is my term. Again, I am still trying to figure what what people
> > mean when they indicate that we as a profession have already learned
> > that "database navigation" is a bad thing. What navigation is bad,
> > what about navigation is bad, and why is it bad. I'm am not
> > interested in anything related to physical navigation but to database
> > navigation at a logical level (the level where a logical data model
> > fits).
>
> I give up. I have no idea what you are talking about.
>
> > What type of navigation do you think that paper is arguing against?
>
> It's arguing against "navigation".

This is such a circular discussion. I apologize if I am making it such. My original question was whether there really is large databased  software that does not have whatever this navigation is that is pooh-poohed. I think that most here will agree that many database folks speak ill of "navigation." I'm trying to figure out what this navigation is that is so bad because I see navigation, database navigation, all over the place and seems to be a viable design pattern, to be employed as any other design pattern (with due diligence to the quality attributes of the product, peformance, maintainability, etc).

I quoted one paper that is mentioned in other writings that speaks against navigation but this navigation seems to be conflated, perhaps, or at least aligned with physical navigation. So, I would like an example of what is spoken against when folks are pooh-poohing navigation. The two examples I gave, were one where an application developer uses output from one query (foreign key value) to "navigate to" another "spot" in the DBMS and the other where the DBMS takes the query plus the metadata specification of a foreign key link and "logically navigates" (that is, I don't care if it sequentially reads the entire medium multiple times at the physical layer, but to the developer the database is navigated). If no one can give an example of bad navigation (at the logical level), then could someone at least tell if either or both of the examples I have provided for navigation are bad and, if so, why.

I very much appreciate any effort given to try to help me understand more precisely what database navigation is considered bad and why. Thanks. --dawn Received on Sat Mar 03 2007 - 00:21:00 CET