- From: Cory Casanave <cory-c@modeldriven.com>
- Date: Tue, 27 Apr 2010 16:50:18 -0400
- To: "Richard Cyganiak" <richard@cyganiak.de>
- Cc: "public-egov-ig IG" <public-egov-ig@w3.org>
Richard, Re: I don't think that you would arrive at such a conclusion after a neutral evaluation of both approaches, to be honest. [cbc] That may be - we have to have a coherent architecture for how all these parts and pieces fit together to provide the fundamental user capability of queriable linked global data projected onto user-focused viewpoints. Without that coherent architecture it is a bit hard to say what the tradeoffs are for a particular issue such as this. -Cory -----Original Message----- From: Richard Cyganiak [mailto:richard@cyganiak.de] Sent: Tuesday, April 27, 2010 4:27 PM To: Cory Casanave Cc: public-egov-ig IG Subject: Re: SPARQL best practice for egov? Hi Cory, On 27 Apr 2010, at 15:30, Cory Casanave wrote: > 2- Community: We are proposing a supposedly simple approach to a > global > data grid. Such a proposal will only be accepted if it works well, is > very simple to use and does not have major usability holes (such as > the > poor relationship between a URI and a query point). The user > perspective must take priority over legacy implementation patterns and > sunk investment of vendors. This technology is at its infancy and > must > not be crippled by a such a tactical perspective, least it fail - and > currently failure is an option. Complex and expensive algorithms to > follow a link are unacceptable. So the two options were: a) make every URI respond to the SPARQL Protocol, b) add a link to every document, and follow that link to another document that tells you where the SPARQL endpoint is. You suggest above that b) has the following problems: - it wouldn't work well, - it has usability holes, - it doesn't take the user perspective into account, - it cripples linked data technology, - it is expensive. I don't think that you would arrive at such a conclusion after a neutral evaluation of both approaches, to be honest. Best, Richard > > -Cory > > -----Original Message----- > From: Richard Cyganiak [mailto:richard@cyganiak.de] > Sent: Monday, April 26, 2010 12:29 PM > To: Cory Casanave > Cc: public-egov-ig IG > Subject: Re: SPARQL best practice for egov? > > Hi Cory, > > On 23 Apr 2010, at 09:16, Cory Casanave wrote: >> We had some discussion about the relationship between a RDF URL and a >> SPARQL endpoint as well as other resources such as graph metadata. >> The >> conclusion seemed to be that there are various vocabularies where a >> triple in the graph could point to the endpoint that points to >> metadata. >> The issue with this is that you would then have to get the entire >> graph >> to get this one triple - which kind of missed the point if you have a >> large dataset that you want to query instead of download. >> >> I can imagine two conventions that could help solve this: >> >> 1) That every resource should respond to a SPARQL endpoint. This >> would >> then allow you to query that one resource directly to subset the data >> and/or to get the triple that points to metadata. > > This option is not feasible IMO because it requires a major revamp of > the organization's web publishing infrastructure. Typically, a SPARQL > endpoint, if provided at all, is located on a different server and is > architecturally separate from the rest of the web server. What you are > asking for requires completely new server software, and I'm not aware > of a single product that currently implements this. > >> 2) That a standard manipulation is done on a URI to get metadata >> about >> resources, which would include the query point. For example: >> http://www.example.com/rdf/people.rfd#cory could have metadata at >> http://www.example.com/rdf/metadata.rdf. There are some existing >> solutions that use this approach. > > The voiD [1] solution is to have a triple: > > <http://www.example.com/rdf/people.rdf> void:inDataset > <http://www.example.com/rdf/metadata.rdf#Dataset >> . > > Resolving <http://www.example.com/rdf/metadata.rdf> would yield a > description of the datset, perhaps including a triple: > > <http://www.example.com/rdf/metadata.rdf#Dataset> void:sparqlEndpoint > <http://www.example.com/sparql >> . > > This exact problem is one of the use cases we had in mind when > creating voiD. Implementation is reasonably straightforward, it > requires publication of the <metadata.rdf> (or <void.ttl>) file, and > one extra link in each RDF file. > > Best, > Richard > > [1] http://rdfs.org/ns/void-guide > > >> >> >> >> Can we set a "best practice" for open government data? My preference >> would be the first. Thoughts? >> >> >> >> -Cory >> > >
Received on Tuesday, 27 April 2010 20:50:43 UTC