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

Re: Public SPARQL endpoints for generic usage

From: Polleres, Axel <axel.polleres@deri.org>
Date: Thu, 8 Apr 2010 07:58:00 +0100
Message-ID: <316ADBDBFE4F4D4AA4FEEF7496ECAEF9035DF674@EVS1.ac.nuigalway.ie>
To: <scorlosquet@gmail.com>, <semantic-web@w3.org>
Hi steph,

Hosting such a thing as a public sparql ep without restrictions has quite obvious security risks.

Could imagine though that this might have potential as a registered service... But don't know anyone providing that yet.

For your simple querie(s) looks like that could be doable without a DB eg using a sparql engine that doesn't reqire a local DB (arq basic) or just an rdf api?



From: semantic-web-request@w3.org 
To: semantic-web@w3.org 
Sent: Thu Apr 08 02:43:45 2010
Subject: Public SPARQL endpoints for generic usage 


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}
    {?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. 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)?


[1] http://www.sparql.org/sparql

[2] http://demo.openlinksw.com/sparql

Received on Thursday, 8 April 2010 06:58:35 UTC

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