If I recall correctly, we considered using blank nodes for such 'intermediate nodes' but decided against them mostly for technical reasons:
DBpedia produces huge N-Triples files. While we write a file, we would have to remember which local names for blank nodes we already used. It seemed easier to simply make sure that the names of intermediate nodes are unique within one page. More importantly, using blank nodes means that you can't easily use multiple N-Triples files together - you'd have to rename thousands of blank nodes. Anyway, that's how I remember these discussions, I'm not 100% sure. Note that intermediate node URIs always contain double underscores, e.g. [1]. Wikipedia doesn't allow consecutive underscores in page titles, so we can be sure that these URIs will not clash with DBpedia URIs for Wikipedia pages. We pick a name from the arguments of the template from which the intermediate node is extracted, append two underscores, that name and a number to the URI of the main page and use that as the URI for the intermediate node. If there are multiple intermediate nodes on one page for which we pick the same name, we use different numbers, e.g. see [1] and [2]. By the way, that both URIs [1] and [2] contain the word "white" is actually a bug... hopefully we can fix that. Christopher [1] http://dbpedia.org/resource/Purple__white__1 [2] http://dbpedia.org/resource/Purple__white__2 On Fri, Mar 2, 2012 at 13:14, Pablo Mendes <pablomen...@gmail.com> wrote: > Bryan, > My understanding matches yours. I think Paul called those "intermediate > nodes": > http://mappings.dbpedia.org/index.php/Writing_Mappings/Templates#Intermediate_Node_Mapping > > Cheers, > Pablo > > 2012/3/1 Bryan Burgers <bryan.burg...@gmail.com> >> >> 2012/2/29 Luis Daniel Ibáñez González <ldiban...@gmail.com> >>> >>> That's it. I'm thinking the answer is "no", but I haven't find any >>> official word about it, so I prefere to ask. >>> >>> Thanks in advance. >> >> >> I don't have the official answer for you, but I don't believe there are >> blank nodes in DBpedia. It appears to me that DBpedia tries to give a URI to >> everything, even if there isn't a corresponding Wikipedia article. I say >> this because I know that there are objects that can be generated using the >> DBpedia Extraction Framework that I would think would be blank nodes, but >> are actually given URIs that aren't directly derived from Wikipedia URLs. As >> an example, run the following query on live.dbpedia.org/sparql. >> >> SELECT ?tm, ?name, ?position, ?squadNumber WHERE >> { >> ?tm a dbpedia-owl:SportsTeamMember; >> dbpedia-owl:team >> <http://dbpedia.org/resource/2011%E2%80%9312_Everton_F.C._season>; >> dbpedia-owl:position ?position; >> dbpedia-owl:squadNumber ?squadNumber; >> dbpedia-owl:currentMember [ rdfs:label ?name ]. >> >> } >> ORDER BY ?squadNumber >> >> >> (http://live.dbpedia.org/sparql?default-graph-uri=http%3A%2F%2Fdbpedia.org&query=SELECT+%3Ftm%2C+%3Fname%2C+%3Fposition%2C+%3FsquadNumber+WHERE%0D%0A%7B%0D%0A++%3Ftm+a+dbpedia-owl%3ASportsTeamMember%3B%0D%0A++++dbpedia-owl%3Ateam+%3Chttp%3A%2F%2Fdbpedia.org%2Fresource%2F2011%25E2%2580%259312_Everton_F.C._season%3E%3B%0D%0A++++dbpedia-owl%3Aposition+%3Fposition%3B%0D%0A++++dbpedia-owl%3AsquadNumber+%3FsquadNumber%3B%0D%0A++++dbpedia-owl%3AcurrentMember+%5B+rdfs%3Alabel+%3Fname+%5D.%0D%0A%0D%0A%7D%0D%0AORDER+BY+%3FsquadNumber&should-sponge=&format=text%2Fhtml&timeout=0&debug=on) >> >> What you get back is a list of players that played for Everton F.C. in the >> 2011–2012 season. Taking one result from that: >> >> >> <http://dbpedia.org/resource/2011%E2%80%9312_Everton_F.C._season__Leighton_Baines__1>, "Leighton >> Baines"@en, "DF"@en, 3 >> >> Leighton Baines has a Wikipedia entry, and therefore a DBpedia URI, but >> this isn't it. This URI doesn't refer to Leighton Baines himself, but rather >> refer's to the concept of Leighton Baines playing for Everton in the >> 2011–2012 season, something that isn't noteworthy enough to have a Wikipedia >> article itself. >> >> I would fully expect this node to be some sort of blank node, but DBpedia >> gives it a URI anyway. This doesn't prove that there are no blank nodes in >> DBpedia, but it lends credence to the idea that DBpedia is trying to give >> URIs to everything, even if there isn't a Wikipedia page for it. >> >> Bryan Burgers >> >> >> ------------------------------------------------------------------------------ >> Virtualization & Cloud Management Using Capacity Planning >> Cloud computing makes use of virtualization - but cloud computing >> also focuses on allowing computing to be delivered as a service. >> http://www.accelacomm.com/jaw/sfnl/114/51521223/ >> _______________________________________________ >> Dbpedia-discussion mailing list >> Dbpedia-discussion@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/dbpedia-discussion >> > > > ------------------------------------------------------------------------------ > Virtualization & Cloud Management Using Capacity Planning > Cloud computing makes use of virtualization - but cloud computing > also focuses on allowing computing to be delivered as a service. > http://www.accelacomm.com/jaw/sfnl/114/51521223/ > _______________________________________________ > Dbpedia-discussion mailing list > Dbpedia-discussion@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/dbpedia-discussion > ------------------------------------------------------------------------------ Virtualization & Cloud Management Using Capacity Planning Cloud computing makes use of virtualization - but cloud computing also focuses on allowing computing to be delivered as a service. http://www.accelacomm.com/jaw/sfnl/114/51521223/ _______________________________________________ Dbpedia-discussion mailing list Dbpedia-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dbpedia-discussion
