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Re: why hierarchy?

From: JOG <jog_at_cs.nott.ac.uk>
Date: 31 Jul 2006 18:21:24 -0700
Message-ID: <1154395284.742962.308190@i42g2000cwa.googlegroups.com>


Neo wrote:
> > > (new 'john 'person)
> > > (new 'frank 'person)
> > > (new 'at 'preposition)
> > > (new 'work)
> > > (create john (create friend at work) frank)
> > > (create frank (select friend at work) john)
> >
> > I am unclear what you have done here not being familiar with your
> > syntax. Could you draw the resulting structure in ascii for me to
> > clarify the results of these instructions.
>
> The simplified, partial structure of the main, top-level things would
> be:
>
> [friend] --------- [At] -----------> [work]
>
> [john] ----- [friendAtWork] ---> [frank]
> <--- [friendAtWork] -----
>

Ok, thanks. So If I had three propositions:

"John is friends with Frank at Work"
"Bob is friends with Sam at Home"
"Tommy is friends with Billy at School"

and (ignoring the bidirectionality for clarity), they would generate:

[ john ] -- [ [ friend ] --- [ at ] --> [ work ] ] --> [ frank ]
[ bob ] -- [ [ friend ] --- [ at ] --> [ home ] ] --> [ sam ]
[ tommy ] -- [ [ friend ] --- [ at ] --> [ school ] ] --> [ billy ]

Now in an RDB I might have a corresponding Friendships relation:



Person Friend Location

john frank work
bob sam home
tommy billy school

For an RDB a simple question like "Which people have friends some place other than at home" requires a statement something of the order of:

SELECT Person from Friendships WHERE Location != "home"

What would the corresponding query be in your system?

> In the 2nd and 3rd lines, the "verb" refers to the first sentence. The
> 2nd and 3rd lines could be "verbs" of some other sentences. This is
> further demonstrated in www.dbfordummies.com/Example/Ex132.asp which
> models complex sentences.
>
> Are you familiar with "Godel, Escher, Bach: An Eternal Golden Braid" by
> D. Hofstadter?
Received on Mon Jul 31 2006 - 20:21:24 CDT

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