Hi, all of these errors stem from the problem that not all RDF triples can be represented in RDF/XML. [1] (IMHO, a shortcoming in the RDF/XML spec that could easily have been fixed by introducing something like <rdf:Property rdf:URI="http://some/uri_(can't_be_xml)">, similar to <rdf:Description rdf:about="http://some/uri";>.)
As Jeen Broekstra wrote on dbpedia-discussion in August 2011 [2]: "The only reliable way around the problem is to use a serialization format that does cope with all legal RDF properly, such as N-Triples or Turtle." But still, when someone really wants RDF/XML, what should Virtuoso do with triples that can't be serialized? In some cases, there actually is a possible representation. For example, the property URI http://dbpedia.org/property/2ndregionalCupApps could be represented as <p:ndregionalCupApps xmlns:p="http://dbpedia.org/property/2";> Weird and confusing for humans, no problem for computers. In those cases that can't be represented in RDF/XML, the spec says 'throw a "this graph cannot be serialized in RDF/XML" exception or error' [1]. Probably not a good solution for us. I think Virtuoso should omit such triples from RDF/XML, but include something like a comment in their place that they were omitted and are available in other formats (like NTriples). Regards, Christopher [1] http://www.w3.org/TR/REC-rdf-syntax/#section-Serialising [2] http://sourceforge.net/mailarchive/forum.php?thread_name=4E443EE5.9020309%40gmail.com&forum_name=dbpedia-discussion On Sun, Feb 26, 2012 at 21:02, Axel Polleres <[email protected]> wrote: > Hi all, > > FWIW, I had posted a similar post/bug-report (also reporting invalid XML on > DBPedia) on the pedantic-web list a while ago: > https://groups.google.com/group/pedantic-web/browse_thread/thread/651ed89bd18e189a# > > best, > Axel > > On 26 Feb 2012, at 12:19, Andreas Harth wrote: > >> Hi Juergen, >> >> On 02/24/12 15:14, Juergen Umbrich wrote: >> > i tried to query some live DBPedia documents but do not succeed since >> > the retrieved content is not valid RDF/XML. >> >> I can confirm that: >> >> $ rapper -c "http://dbpedia.org/resource/French_Guiana"; >> rapper: Parsing URI http://dbpedia.org/resource/French_Guiana with >> parser rdfxml >> rapper: Error - URI /data/French_Guiana.xml:158 - Using property element >> 'Description' without a namespace is forbidden. >> rapper: Error - URI http://dbpedia.org/resource/French_Guiana - >> Resolving URI failed: Failed writing body (0 != 1188) >> rapper: Failed to parse URI http://dbpedia.org/resource/French_Guiana >> rdfxml content >> >> I've also seen unescaped &'s in DBpedia. >> >> I've cc'ed [email protected] to notify the >> DBpedia guys. >> >> Best regards, >> Andreas. >> >> PS. there's been several issues mentioned lately, e.g. Axel's mail >> from 2012-01-04, or my mail from 2011-08-09 on [email protected]. >> > ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ Dbpedia-discussion mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/dbpedia-discussion
