(This page is still under construction.)


Some help (such as sample SPARQL queries) can be found on answers.semanticweb.com and/or Stack Overflow. The most recent 10 posts for each site should be seen in the Feeds section, lower down on this page. Full searches are linked here --


If the information you need cannot be found there, you can:

  1. create a new post on one of the Overflow sites and use the tag “dbpedia”
  2. check the DBpedia support page .

Feeds

(Still not displayed correctly, we are working on aggregating the feed)

answers.semanticweb.com

Link ontologies from DBpedia to external ones with sameAS

Is there a way in SPARQL to automatically connect instances of one ontology in DBpedia and another in a different database. For example

http://yago-knowledge.org/resource/Daphne_Gere and http://dbpedia.org/page/Daphne_Gere

are similar and connect with the propriety sameAs, but I would like to be able to do it for all instances of the ontologies where they belong

http://yago-knowledge.org/resource/wordnet_actor_109765278 and http://dbpedia.org/ontology/Actor

So for example the result will be a table that has all the instances from one class with their equivalent in the other class.

Why are SPARQL FILTER directives with a Regex ignored in some queries on DBpedia?

I am trying to retrieve property URIs along with their (declared or actual) ranges from DBpedia. I want to restrict the properties to URIs that contain a certain substring.

My first attempt was this:

SELECT DISTINCT ?property ?range WHERE 
{  
   ?s ?property ?object.  
   FILTER(regex(str(?property), 'birth', 'i')).
   BIND(datatype(?object) AS ?range).
   OPTIONAL {?property <http://www.w3.org/2000/01/rdf-schema#range> ?range. }
} LIMIT 10

Upon sending this query, DBpedia returns the following values for ?property:

http://www.w3.org/1999/02/22-rdf-syntax-ns#type     
http://www.w3.org/2002/07/owl#sameAs    
http://purl.org/dc/terms/subject    
http://dbpedia.org/ontology/Person/height
http://dbpedia.org/ontology/PopulatedPlace/areaTotal
http://dbpedia.org/ontology/PopulatedPlace/populationDensity
http://dbpedia.org/ontology/Work/runtime
http://dbpedia.org/ontology/abstract
http://dbpedia.org/ontology/birthPlace
http://dbpedia.org/ontology/birthDate

Evidently, this list contains several URIs that do not contain the substring birth. (The result is the same when using the contains function rather than regex.)

If I remove the lines starting with BIND or OPTIONAL, everything is as expected:

SELECT DISTINCT ?property WHERE 
{  
   ?s ?property ?object.  
   FILTER(regex(str(?property), 'birth', 'i')).
} LIMIT 10

returns

http://dbpedia.org/ontology/birthDate
http://dbpedia.org/ontology/birthPlace
http://dbpedia.org/ontology/birthYear
http://dbpedia.org/property/birthDate
http://dbpedia.org/property/birthPlace
http://dbpedia.org/property/dateOfBirth
http://dbpedia.org/property/placeOfBirth
http://dbpedia.org/ontology/birthName
http://dbpedia.org/property/birthName
http://dbpedia.org/property/birthname

i.e. only properties whose URIs contain the substring birth.

What am I doing wrong?

Which are the DBpedia entities of type Agent that are not of type Thing?

Hi,

I'm trying to extract the DBpedia entities that has "rdf:type Agent" and has not "rdf:type owl:Thing". I wrote this query:

PREFIX dbpedia-owl: http://dbpedia.org/ontology/ SELECT ?entity { ?entity rdf:type dbpedia-owl:Agent . FILTER NOT EXISTS { ?entity rdf:type owl:Thing } }

Something strange happens in the results. The first 8 results, have "rdf:type Agent" and have not "rdf:type owl:Thing". The 9th result, Management, has no rdf:type but in the top of the page there's "An Entity of Type : Thing".

This is quite strange because in the query is specified that ?entity must be of type Agent. Moreover, the query specified to filter the entity with type owl:Thing with the FILTER operator.

How this is possible?

Thanks in advance Fabio

How to find a relationship between two resources on DBpedia?

Hello all,

if a have two resources, for example: http://dbpedia.org/resource/France and http://dbpedia.org/resource/Mitsubishi

[the Two resources : France and Mitsubishi]

How can I get the relations between these two resources using SPARQL queries?? and I mean by relation (is a - has a ) or some thing like that?

DBPedia Local Store and comparing it with other semantic database

Hello, I want to setup a local store which will have all the dbpedia data and similar semantic rdf data. I want to compare the classes and bring a union of the properties matching in all the semantic rdf files. For example if i query about a place in dbpedia and again in openlink then I want to compare the results and give more ratings to only the properties which match. Also i want the dbpedia updates to be synchronized. I also need to know what type of database table structure i will need if i have to integrate this data in my database. I need to know what hardware and software i need to do this. I also need to know whether any paid/free service is available for doing this activity. Sorry if i am not clear by i can give some more explainations.

Where to look for mapping of prefix

In Live Dbpedia there is a property prop, what is the mapping for this?

PREFIX prop: ??????

In general how do I look up mapping for a PREFIX?

The page I look at is at Live Dbpedia link text . The property I want to use is prop:years.
The same info is at Dbpedia link text. The propety dbpprop:years is a list instead of a single value as in prop:years. So I think prop is not dbpprop

Note: if you land on the old live.dbpedia on the first link, click Try New Dbpedia. I copy the link from the New Dbpedia and did not realize that the link would land on the Old one.

How to sort on the second item of a property

I try to sort on a property, but this property is a list and the sorting is on the first item. How do I sort on the second item. This is my query

PREFIX dbpprop: <http://dbpedia.org/property/>

SELECT DISTINCT ?s ?y
WHERE {  
    ?s dbpprop:title dbpedia:List_of_tallest_buildings_in_Vietnam .
    ?s dbpprop:years ?y .
}
ORDER BY DESC(?y)

And the property y has values year and height. The sorting is on the year and I would like to sort on height.

steps to link my data

hi, if i want to link my data to bdpedia should i map my data to the lod vocabulary first ??? or i can link my data to dbpedia just by making links like this : <owl:ontology rdf:about="">

<owl:imports rdf:resource="http://dbpedia.org/resource/Almond"/>

<owl:thing rdf:id="almond">

<owl:sameas rdf:resource="http://dbpedia.org/resource/Almond"/>

<Ontology1399520089494:origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string"

vegetarian</ontology1399520089494:origin>

<Ontology1399520089494:type rdf:datatype="http://www.w3.org/2001/XMLSchema#string"

dried fruit</ontology1399520089494:type>

<rdf:type rdf:resource="#naturel"/> </owl:thing

if i make thiselinks and then i publish my data in datahub sites does it mean that i can access to dbpedia ?? please help because i'm lost thanks in advance

linked data with TopBraid composer

hi , if i use TopBraid Composer to link my ontology to DBpedia(using same as and owl:import property) and then publish my ontology using puppy does it mean that i can access to dbpedia ?? and get all the comment about almond inn dbpedia ?? for exemple if i have :

<owl:ontology rdf:about="">

<owl:imports rdf:resource="http://dbpedia.org/resource/Almond"/>

<owl:Thing rdf:ID="almond">

<owl:sameAs rdf:resource="http://dbpedia.org/resource/Almond"/>

<Ontology1399520089494:origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string"

>vegetarian</Ontology1399520089494:origin>

<Ontology1399520089494:type rdf:datatype="http://www.w3.org/2001/XMLSchema#string"
>dried fruit</Ontology1399520089494:type>

<rdf:type rdf:resource="#naturel"/>

</owl:thing>

how can i publish my data using the mechanism of OWL import

hi , after reading i understand this : - if i want to publish my vocabulary as linked data i have to explicitly use a lod vocabulary(foaf or dc) in my vocabulary _ or i can use the mechanism of OWL import i'm right ??

how can i use the mechanism of owl import to link my data ?? what is the difference between these two approaches

please help me because i'm confused thanks in advance



 
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Last Modification: 2011-07-24 20:04:59 by Sebastian Hellmann