W3C home > Mailing lists > Public > semantic-web@w3.org > January 2008

Re: semantic data models

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Sat, 5 Jan 2008 11:14:21 -0500
To: <editor@content-wire.com> <editor@content-wire.com>
Message-Id: <8422A869-9172-4AF3-BCC8-B0CBFDB47202@gmail.com>
Cc: "Danny Ayers" <danny.ayers@gmail.com>, <semantic-web@w3c.org>

On Jan 5, 2008, at 3:56 AM, <editor@content-wire.com> <editor@content-wire.com 
 > wrote:

> Danny
> I tried to answer some of questions below myself - done more reading  
> in the meantime
> I have sent you my draft under separate cover for you to check
> (some information is still missing)
> I need to add a section explaining to web mortals what is a sparql  
> endpoint, and why should they know
> perhaps you can help me here too...
> The SPARQL query language can be used on such data, and because
>>> of the use of URIs as identifiers it's inherently Web-friendly.
> I read with interest the tutorial (could not reach phil mccarthy on  
> gmail)
> http://www.ibm.com/developerworks/xml/library/j-sparql/
> I do however have the following questions:
> 1) definition of sparql = As 'sparql endpoint' is a URI where a
> concatenation of RDF triples can be queried
A SPARQL endpoint is a service  that accepts SPARQL queries as HTTP  
GET or POSTs and returns the query results in one of several formats,  
e.g. xml, json, etc, as the http response.
> 2) do I need a semantic web browser/tool to query a sparql endpoint?
Technically you can do it in a browser, but the form of the URL is  
ugly. (see, e.g, the second set of slides at http://esw.w3.org/topic/HCLS/Banff2007Demo) 
  So more commonly you would use interfaces, from the very basic (http://sparql.neurocommons.org:8890/nsparql/ 
) to much more interesting ones, such as relfinder below (and many more)
> 3) I pointed my firefox browser to http://esw.w3.org/topic/SparqlEndpoints
> and all I got was 503 or other errors, could not get anywhere near  
> the endpoint  or anything that looked like an endpoint
> any idea where is the problem? is it in the connection? in the  
> browser?
Our presentation gives the active location of the endpoint for the  
HCLS/Science Commons triple store.
> 4) do you see in the future that I ll be able to use a 'standard'
> browser and web interface to query an rdf graph?
Yes, there are a getting to be quite a few. E.g

> is that asking for too much to have a high level interface that does
> the sparql queries for me? (Ideally, I would just to a website and  
> enter a natural language query, like i do with any current search  
> engine, and all the linking should be done at the backend. I hope I  
> am not expected to learn how to write sparql queries to navigate rdf  
> graphs?
> or is it?
You are not expected. SPARQL is an architectural component for  
enabling exactly such interfaces on the web. But crucially, since it  
is open, by exposing your data via a SPARQL endpoint you are letting  
many people work on different ideas for how to interface to the data.  
Compare this to the current state of web services which are typically  
backed by a relational database that itself is not exposed, and for  
which a different xml schema is created for each different kind of  
data (if you are lucky).


> thanks
> (suffering)
> pdm
>>> http://www.w3.org/2001/sw/
>>> also:
>>> http://sites.wiwiss.fu-berlin.de/suhl/bizer/pub/LinkedDataTutorial/
>>> To make it useful internally, you may want to check out some of the
>>> available tools, e.g. at:
>>> http://www.mkbergman.com/?page_id=325
>>> http://sites.wiwiss.fu-berlin.de/suhl/bizer/toolkits/
>>> http://planetrdf.com/guide/
>> thanks a lot Danny - I am collecting points of view at the moment
>> most useful
>> best
>> pdm
>>> Cheers,
>>> Danny.
>>> -- 
>>> http://dannyayers.com
Received on Saturday, 5 January 2008 16:14:31 UTC

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