Re: Ideas for World Hierarchy Example

> > Lat: 1.2345 / Long: 4.5678 Lat: 5^ 6' 8"N / Long: 2^ 3' 4"E
> > Are these both cartesian?
>
> No. Both are polar coordinates. In 3D polar coordinates you have three
> values.. Latitude, Longitude,. radial distance from the centre..
> A Cartesian coordinate would take some predefined reference point and
> then describe the distance north/south and east/west and possibly
> up/down as well.

I feel I have been wiki-fied. Thanks.

> > > The difference between a hierarchical and relational database is not in
> > > the data they hold, but in the route used to navigate to the data.
> >
> > ... path to the latitude of the location of the Golden Gate Bridge:
> > universe \ milky way \ solar system \ earth \ continent \ north america
> > \ usa \ state \ california \ city \ san francisco \ world wonder
> > \ golden gate bridge > location > latitude > 37^ 49' 10" N
>
> That's one path to the bridge, there are a lot of others.
> You could, for instance, divide the world's bridges into ...

In the mind of an average person, yes, there are many. In the mind of a db, only those it has been told. For example, in the current dbd db, SFGG Bridge can be accessed via the following queries based on classification, name and location:

(get (. 'world 'wonder) instance *)
(get * name (get 'golden 'gate 'bridge))
(get * location (& (get location instance *)
                         (get * latitude '37^49'10"N)
                         (get * longitude '122^28'43"W)))

Also instead of navigating the db\item\universe... route to the bridge in the tree view interface, one can use the following alternate paths:

db\item\world wonder
db\item\city\san francisco\ ...
db\item\state\california\ ...
db\item\country\usa\ ...
db\item\continent\north america\ ...
db\item\earth\ continent\ ...

And if one navigated to SF Bridge via db\item\world wonder, he can find out where else it is referenced by issuing "Find Where Referenced" command which in this case would find san francisco.

> I think you have the cart before the horse. Fixed categories mimic the
> fixed table structure of relational databases, and if you are going to
> go that route then you should probably use a relational database. You
> won't gain anything from using the hierarchical model.

Luckily, iddy biddy dbd doesn't use the Hierarchal, Relational, Binary, Graph, CODYSL Network, XML, ProLog, LISP, hyperNotePad or bitBucket model :) It does use a tree and grid to view data.

> Instead consider allowing users to create hierarchies on the fly,
> depending on the data they have and the uses they want to put it to.

But user's can create hierachies on the fly with data they have.

> that point you need to ask for some help from the people here who have a
> deep understanding of the relational model, because you will then face a
> problem that they haven't yet solved either.

Can you describe what that problem is? Possibly with respect to the current World Hierarchy Example? Who knows, maybe I already accidently solved it :)

> How about turning the collective brainpower of the group on a
> constructive task: design a workable computer-based EAV system.

What does it need to do that a regular db doesn't already? Can you give an example?

> librarians built theirs 200 years ago, and it has been largely unchanged
> since Mr Dewey used Mr Aristotle's classification methods to create it.

Can things in the Dewey system have multiple classifications?

> Can we do better in the 21st century?

What would make it better? Received on Mon Jan 15 2007 - 02:01:07 CET