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Re: RDF IG meeting at W3C Technical Plenary 2001-02-28

From: Seth Russell <seth@robustai.net>
Date: Sat, 10 Feb 2001 12:56:10 -0800
Message-ID: <3A85AAEA.609B2792@robustai.net>
To: David Allsopp <dallsopp@signal.dera.gov.uk>
CC: www-rdf-interest@w3.org
David Allsopp wrote:

> Seth Russell wrote:
>
> > Personally I don't believe we want a query language outside of RDF .. we
> > want it inside RDF.   In other words we should be able to express a
> > question in RDF.
>
> If we express queries in RDF, and parse them into a Model, how does the
> query engine access them in order to carry out the query?  By querying
> the model...?
>
> [ OK, I guess you'd probably only need Model.find(s, p, o), but the
> circularity amuses me. 8-) ]

Obvioulsy any angent who might answer the question needs to know it is a
question.  In the example below I think I have adequeately identified that
situation.

> My first concern is that some of the proposed queries expressed in RDF
> are pretty much unreadable, and extremely verbose, at least in M&S
> syntax, which may partly explain why people tend to go for SQL-like
> query syntax, which, after all, just expresses a graph with variables in
> a cleaner way.

Actually I think it falls on the other side.  Putting the variables (via
pronouns) directly in the RDF will be far more readable and far shorter - your
welcome to take a stab at my example below in your favorite query language.
Bear in mind that to write a query you must know the exact property names in the
destination model that might yield the answer.  This will not normally be the
case for practical applications if you factor in the diversity of the semantic
web.  The person asking the qusetion knows only the definition of the question
in their terms;  they lack the  knowledge of how the answer might be expressed
inside of your internal system;  therefore they will not normally have enough
information to write a query to you data base.   We need to define a process
between the question and the query where translations of property equivaentTo(s)
and inverseOf(s) and other kinds of inferences happen; and/or the question is
servered up to a human agent in a language that is comprehensible.

> (I've been very struck by the similarity between the SQL-like queries,
> and N3 - I had a spooky feeling when I was playing around with some RDF
> query syntax like N3, then on the same day found the pages on N3 for the
> first time!)

If you liked N3, you'll love SemEnglish (see below).  Note that is can be
legitimately embedded in XML, is cleaner and easier to read and write.
Incidentally, my signature example asks a real question ... the answer to which
I really do want to know.  (hmmm.... i wonder if i can say that any plainer).

<signature
       language="SemEnglish"
       fromDictionary="http://webns.net/roughterms/#"
       context="ThisEmailTrain"
       intent="toRecieveAnswer">
Seth
     preferedEmail "seth@robustai.net";
     properName "Seth Russell";
     asks [Who#x willProgram Sembrowser].
Who#x
     worksWellWith Seth;
     fluentIn RDF, N3, VB, VFoxPro, "C++", SQL;
     canEasilyLearn BerkeleyDB;
     salaryRequirements "0".
BerkeleyDB
     see [http://www.sleepycat.com/].
Sembrowser
     description "Semantic Web Browser";
     aka MyMemory, ContexBrowser, Emouth, CyberMind;
     willBeLike [Moasic wasTo Www].
SemEnglish
     see [http://robustai.net/mentography/semenglish.html].
</signature>
Received on Saturday, 10 February 2001 15:47:29 GMT

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