This slide set is a provided by the SESAM4 consortium as one out of three Technology Primers on Semantic Web technology. This Primer is on SPARQL and gives you a short introduction to its constructs followed by some examples. You can find the belonging slideset at youtube under SESAM4.
8. SPARQL - “DESCRIBE” Suppose The only thing you have is an Uri like this And no idea what is known about it.... http://data.esis.no/resource/projectID_111667 Simply send a SPARQL “DESCRIBE” to a sparql endpoint DESCRIBE <http://data.esis.no/resource/projectID_111667>
11. SPARQL - “SElect” ... or you know what to look for and want to select specific resources. Send a sparql “select” to a sparql endpoint PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX dct: <http://purl.org/dc/terms/> PREFIX nfr: <http://data.esis.no/resource/> PREFIX foaf: <http://xmlns.com/foaf/0.1/> SELECT ?projectID ?projectName WHERE { ?projectID a foaf:Project ; dct:title ?projectName ; nfr:orgnrResponsibleOrg <https://ws.brreg.no/lod/enhet/962392687> . }
Retorics: - where before information was locally managed, using local keys, and only accessible through customised interfaces using these “local keys” to identify information … … today this very same information is available from many different sources, represented in a standard way using globally unique identifiers … .. which are connected to each other and in such a way provide explicit key-references between different data-sets which can be used for automated harvesting and discovery
So now you think: - this is too large, too complex and too big. I cannot possible see how I can work with this and yes: I cannot see what is wrong with normal relational databases and SQL querying .. - well there is good and bad news. The good news is that it is indeed BIG, the bad news is that it is also complex and maybe even huge. … - But there is more good news: some smart people at W3C have found a way to let you use this graphs using a query language which is very similar to SQL, called SPARQL.
