W3C home > Mailing lists > Public > semantic-web@w3.org > April 2010

Re: Public SPARQL endpoints for generic usage

From: Alexandre Passant <alexandre.passant@deri.org>
Date: Thu, 8 Apr 2010 11:08:34 +0100
Cc: semantic-web@w3.org
Message-Id: <0C9AE055-E2C0-4C43-AE86-14E33F195706@deri.org>
To: Stephane Corlosquet <scorlosquet@gmail.com>
Hi,

On 8 Apr 2010, at 02:43, Stephane Corlosquet wrote:

> Hi,
> 
> Some applications don't have the capability or the resources to run SPARQL queries themselves and must rely on external services. There exist a few SPARQL public endpoints which allow generic SPARQL querying [1] [2]. Are there any policy on using these public endpoints in applications? I understand these were setup primarily for educational purposes. Obviously anyone wanting to build a reliable service would host their own SPARQL endpoints, but how about situations where the user setting up an application using SPARQL is not able to host such a service. Think of handheld devices, or situations where no SPARQL library is available for software stack an application runs on. 
> 
> The use case which prompted me to write this email is in PHP where ARC2 requires MySQL to run SPARQL queries. During the installation of Drupal, imagine we want to get all the classes of a vocabulary with:
>   select *
>   from <http://xmlns.com/foaf/0.1/>
>   where {
>     {?class rdf:type owl:Class}
>     union
>     {?class rdf:type rdfs:Class}.
>     OPTIONAL {?class rdfs:label ?label}.
>   }
> (similarly for properties)
> 

> Sites running on a database other than MySQL will need to use an external SPARQL endpoint. I imagine this is not an isolated use case.


You can have a look at RAP [1], it provides in memory SPARQL capabilities [2].

Best,

Alex.

[1] http://www.seasr.org/wp-content/plugins/meandre/rdfapi-php/doc/
[2] http://www.seasr.org/wp-content/plugins/meandre/rdfapi-php/doc/tutorial/usingtheSparqlEngine.htm


> Do we have public endpoints available for this sort of (ideally lightweight) querying? How do they deal with server load (API key, IP based flooding control)?
> 
> Steph.
> 
> [1] http://www.sparql.org/sparql
> [2] http://demo.openlinksw.com/sparql

--
Dr. Alexandre Passant
Digital Enterprise Research Institute
National University of Ireland, Galway
:me owl:sameAs <http://apassant.net/alex> .
Received on Thursday, 8 April 2010 10:09:14 UTC

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