linked-data

问题 I'm trying to copy the data from a Sesame repository to another triplestore. I tried the following query: ADD <http://my.ip.ad.here:8080/openrdf-workbench/repositories/rep_name> TO <http://dydra.com/username/rep_name> The query gets executed with output as 'true' but no triples are added. So, I tried a similar query to see if I can move data from one Sesame repository to another using SPARQL Update: ADD <http://my.ip.ad.here:8080/openrdf-workbench/repositories/source_rep> TO <http://my.ip.ad

问题 I have problem with SPARQL. I want to select something from category. For example subjects. I make query like this in http://dbpedia.org/snorql. SELECT ?category ?subject WHERE { ?category a skos:Concept . ?category skos:Concept: American_punk_rock_guitarists. ?category dct:subject ?subject . } LIMIT 1000 I have error Virtuoso 37000. I don't understand why. P.S. Is it good book for beginnier in SPARQL - Learning SPARQL, 2nd Edition Querying and Updating with SPARQL 1.1 ? 回答1: You have at

问题 Following this qeustion: Summer in Greece with SPARQL, since my memory runs out when executing this query, I would like to constrain the query between two regional units, but I can't group them: SELECT * #?municipality (?bwCount1+?bwCount2 as ?bwCount) WHERE { { SELECT (COUNT(?bw) as ?bwCount1) WHERE { ?regional_unit geo:έχει_επίσημο_όνομα "ΠΕΡΙΦΕΡΕΙΑΚΗ ΕΝΟΤΗΤΑ ΗΡΑΚΛΕΙΟΥ" . ?municipality1 geo:ανήκει_σε ?regional_unit . ?municipality1 geo:έχει_γεωμετρία ?geometry . ?bw geos:hasGeometry ?bw_geo

问题 I am building a web page that lists typical dishes for each individual country. Each dish is put in its own article and all of that goes fine. But I wonder if there is a way to link the Recipe s to the country. Does it make sense to also specify the country with http://schema.org/Country, and if so how can I link that to the dishes? I thought about defining the main as a country, and then using http://schema.org/additionalProperty but that doesn't seem to make sense as it expects a

问题 This question already has an answer here : Exclude results from DBpedia SPARQL query based on URI prefix (1 answer) Closed 3 years ago . You can run the query below at the Linked MDB SPARQL Explorer. The values of ?imdbID (the last variable) contains IRIs from one of three possible domains (freebase.com, rottentomatoes.com or imdb.com). I would like to know how to apply a filter such that only the rows from the imdb.com domain are retained. PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>

问题 What is the difference between rdf:seeAlso and rdfs:seeAlso ? When I can use rdf:seeAlso and when I can use rdfs:seeAlso ? Can you do any examples? 回答1: First, note that rdf and rdfs are prefixes commonly used to reference the RDF syntax and RDF schema vocabularies respectively. The rdf is typically used for http://www.w3.org/1999/02/22-rdf-syntax-ns#, so that rdf:seeAlso would expand to http://www.w3.org/1999/02/22-rdf-syntax-ns#seeAlso. However, if you follow the vocabulary reference, you

问题 The data representation I will try to use for a RESTful API is JSON-LD and the vocabulary I intend to use are those from schema.org . In the vocabulary schema.org/GeoShape, it says that polygons are expected to be on text format but it doesn't exactly say what kind of text format. It wasn't also stated that it should use the WKT Polygon format. WKT Polygon Format (Well-known Text) POLYGON ((30 10, 40 40, 20 40, 10 20, 30 10)) However, since I will be representing data using JSON-LD, it may

问题 I read this blog article, Problems of the RDF model: Blank Nodes, and there's mentioned that using blank nodes can complicate the handling of data. Can you give me an example why using blank nodes is difficult to perform a SPARQL query? I do not understand the complexity of blank nodes. Can you explain me the meaning and semantics of an existential variable? I do not understand clearly this explanation given in the RDF Semantics Recommendation, 1.5. Blank Nodes as Existential Variables. 回答1:

问题 I have recently started working with semantic web and linked data technologies, I have been always confused about one thing though. What is the difference between an Ontology and a vocabulary? Which is preferable? 回答1: In the driest sense, a "vocabulary" is a context-less list of terms, with no defined interrelationships. "Ontology" is meatier, implying the presence of interrelationships, axioms, classes, etc. Nevertheless, the term "vocabulary" is almost never used to mean ONLY "list of

问题 I am trying to fetch a list of American movies adapted from books from dbpedia. This is what I have so far: PREFIX onto: <http://dbpedia.org/ontology/> PREFIX dcterms: <http://purl.org/dc/terms/> SELECT * WHERE { ?movie dcterms:subject <http://dbpedia.org/resource/Category:American_films> . ?movie dcterms:subject <http://dbpedia.org/resource/Category:Films_based_on_novels> . ?movie onto:basedOn ?book . ?book a onto:Book . } I get only 4 results back. Is there another property I can use to get