On 1/11/13 9:44 AM, Augusto Herrmann wrote:
Hi, Kingsley!Thanks for the suggestion. Virtuoso's faceted browser certainly does allow you to browse the data. But I've looked at the URIs in the examples you provided and AFAIK it won't give those nice dereferenceable URIs as required and described in the Linked Data API spec [1], and seen on the UK's linked data efforts (e.g. [2], [3]).The only Linked Data API implementations I've found so far are Elda [4] (Java) and Puelia [5] (PHP). So far we've been using Elda, with satisfactory results.[1] http://code.google.com/p/linked-data-api/wiki/Specification [2] http://education.data.gov.uk/ [3] http://environment.data.gov.uk/doc/bathing-water/ukl1702-36800 [4] http://code.google.com/p/elda/ [5] http://code.google.com/p/puelia-php/
The faceted browser suggestion was more to do with an interface for exploring your Virtuoso instance. It isn't an option for Linked Data deployment. You can use Virtuoso's in-built features for Linked Data deployment as an option, if need be.
Kingsley
Best regards, Augusto HerrmannOn Thu, Jan 10, 2013 at 5:24 PM, Kingsley Idehen <[email protected] <mailto:[email protected]>> wrote:On 1/10/13 12:23 PM, Augusto Herrmann wrote:Hi, Chris and Kingsley, thanks for the tip! We got it working now by adding the triple [1]: <http://orcamento.dados.gov.br/sparql/> elda:supportsNestedSelect true . The SPARQL query generated by Elda is much simpler, now. Works beautifully. [1] http://dev.dados.gov.br/codigo/outros/orcamento-linked-data/changeset/0eb507b1a891033cfbb60c985ccbe6017df2d435#aspecsorcamentottl_n28 <http://dev.dados.gov.br/codigo/outros/orcamento-linked-data/changeset/0eb507b1a891033cfbb60c985ccbe6017df2d435>Great! Why not install Virtuoso's faceted browser engine [1], via the Faceted Browser VAD so that you have a powerful Precision Search & Find service in place. Examples: 1. http://beta.bio2rdf.org/ -- note the "search" option links 2. http://bit.ly/ZLt002 -- LOD Cloud Analytics re. UK Schools by Authority 3. http://bit.ly/WSkaav <http://bit.ly/UqyqZa> -- LOD Cloud Analytics re. UK Schools by District . Links: 1. http://virtuoso.openlinksw.com/dataspace/dav/wiki/Main/VirtFacetBrowserInstallConfig . KingsleyBest regards, Augusto Herrmann On Thu, Jan 10, 2013 at 12:35 PM, Kingsley Idehen <[email protected] <mailto:[email protected]>> wrote: On 1/10/13 7:44 AM, chris dollin wrote: On 10 January 2013 12:03, Augusto Herrmann <[email protected] <mailto:[email protected]>> wrote: Greetings! We're implementing a Linked Data API for the Brazilian federal budget [1], using Elda, in a similar way the UK government has done with some of its open data. It's still in an early alpha stage, though. What we're having difficulty with is defining the Views for the item-de-despesa [2]. In our spec [3], we can's even list all the properties lest the SPARQL query becomes too complex for Virtuoso to handle. Even with only a few properties, if the user chooses to list 25 or more items per page, the query breaks. We've looked at the schools example view [4] and it looks quite similar, but the generated SPARQL query is much simpler. Does any one have a clue on what's wrong with the views we're defining? [1] http://orcamento.dados.gov.br/ [2] http://orcamento.dados.gov.br/doc/item-de-despesa [3] http://dev.dados.gov.br/codigo/outros/orcamento-linked-data/files/305212de5f6852e447ea13bae4afa5cbf47f99b5/specs/orcamento.ttl#L47 [4] http://code.google.com/p/linked-data-api/source/browse/trunk/examples/config/education.data.gov.uk.ttl#35 Does Virtuoso implemented nested SELECTS and have you enabled them in your Elda config? Without nested selects, the core of a View query is repeated for every selected item. If the view core is big, the entire query is enormous, and can blow up buffers between Elda and the SPARQL endpoint. "Enormous" meaning multiple megabytes. Which is why Elda has the nested select option ... Chris (Stuart may have some other ideas.) Add virtuoso list to the cc. Virtuoso supports SPARQL subqueries. I've provided an example here: http://bit.ly/UNaKyA .--Regards, Kingsley Idehen Founder & CEO OpenLink Software Company Web: http://www.openlinksw.com Personal Weblog: http://www.openlinksw.com/blog/~kidehen <http://www.openlinksw.com/blog/%7Ekidehen> Twitter/Identi.ca handle: @kidehen Google+ Profile: https://plus.google.com/112399767740508618350/about LinkedIn Profile: http://www.linkedin.com/in/kidehen--Regards, Kingsley Idehen Founder & CEO OpenLink Software Company Web:http://www.openlinksw.com Personal Weblog:http://www.openlinksw.com/blog/~kidehen <http://www.openlinksw.com/blog/%7Ekidehen> Twitter/Identi.ca handle: @kidehen Google+ Profile:https://plus.google.com/112399767740508618350/about LinkedIn Profile:http://www.linkedin.com/in/kidehen ------------------------------------------------------------------------------ Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft MVPs and experts. ON SALE this month only -- learn more at: http://p.sf.net/sfu/learnmore_123012 _______________________________________________ Virtuoso-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/virtuoso-users
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