Linked Data: First Blood

Knowing a lot about something, makes me more prone to appraising its value. I unfortunately know very little about Linked data. For this reason, I’ve had a very biased and shamefully low opinion about the concept of linked data. I’ve decided to change this.

A repository of linked data that I’ve recently taken an interest in, is DBPedia. DBPedia is a project about extracting structured data (linked data) from Wikipedia, and exposing it via a SPARQL endpoint. With the interested in DBPedia, comes the first sparks (pun intended) of interest in RDF-endpoints and in particular SPARQL.

The brilliant thing about DBPedia (and SPARQL) is that it makes it possible to query a vast repository of information, originally in raw text form, using a proper query language. It’s Wikipedia with a nerd boner on.

So what can you do with SPARQL and DBPedia? There are several examples on the DBPedia homepage.

Here is one (slightly modified one): Find all people born in Copenhagen before 1900 (the link points to a page that executes the query):

PREFIX dbo: <http://dbpedia.org/ontology/>
 
SELECT ?name ?birth ?death ?person WHERE {
     ?person dbo:birthPlace :Copenhagen .
     ?person dbo:birthDate ?birth .
     ?person foaf:name ?name .
     ?person dbo:deathDate ?death .
     FILTER (?birth < "1900-01-01"^^xsd:date) .
}
ORDER BY ?name

Looking at the names that are returned, I believe that those are names of people born in Copenhagen before 1900. A test probe looking up one of the people on the list confirms it. According to Wikipedia, Agnes Charlotte Dagmar Adler was a pianist born in Copenhagen in 1865.

Ok, the hello world of linked data has been commited to this blog. This will NOT be the last thing I write about Linked Data… I’ve seen the light.

This blog post is dedicated to Anders Friis-Christensen, who tried (without luck) to get me interested in Linked Data two years ago. I might be a bit slow, but I eventually get it 🙂

Leave a Reply