Just popping in to say wow - that is a fantastic contribution, great work! On Thu, Nov 13, 2014 at 1:16 PM, Mike Bryant <[email protected]> wrote:
> First of all, thanks very much for this. It looks great! > > My personal interest is being able to query standard Neo4j property graphs > via SparQL and export them as triples. To some extent you can currently do > this using the Blueprints PropertyGraphSail, but where I'm lacking the > knowledge and insight (and time to research!) is in creating mapping > schemas or using some inference step to produce triples such that "property > X of node/edge with label Y = Z", adding domain-specific semantics. > > I too will be keen to here more details about this. > Cheers, > ~Mike > > On Thursday, 13 November 2014 11:47:57 UTC, Michael Hunger wrote: >> >> Interesting. >> I always wondered if it was possible to transform RDF to a more compact >> property graph model on import but still allow RDF queries / export on top >> of that. >> This would be more efficient both in space and performance but more >> involved at the import stage. >> >> E.g. all rdf triples that identify "properties" would be transformed into >> real properties and relevant type/ontology information would be (also) >> transformed into Labels. >> Only the "real" semantic relationships that add value to the domain would >> kept as actual relationships but potentially augmented with properties too. >> >> One could also imagine a "graph optimization applied to the RDF graph" >> that does the above but leaves the original RDF model in Neo4j but uses the >> optimized version for more efficient querying? >> >> Cool, then perhaps we can meet somewhere in Germany (Berlin, Frankfurt), >> or you can come over to our Malmö office for a meetup to show it off? >> >> Looking forward to your blog post. I'd love to see a complete roundtrip >> covered, from import to queries and inference. >> >> If you need anything from me, please ping me. >> >> Cheers, Michael >> >> >> On Thu, Nov 13, 2014 at 12:11 PM, Niclas Hoyer <[email protected]> >> wrote: >> >>> >>> Do you have any information about the model you use to store RDF >>>> efficiently and any performance numbers? Esp. comparing it with cypher? >>>> That would be really interesting. >>>> >>> The plugin is based on the blueprints framework and the "SAIL >>> Ouplementation >>> <https://github.com/tinkerpop/blueprints/wiki/Sail-Ouplementation>". A >>> RDF triple is mapped as a directed edge. All information is stored in the >>> properties. So e.g. a URI node in RDF <http://example.com> is mapped as >>> ({kind: "uri", >>> value: "http://example.com"; }). The URI of an edge is represented as >>> type of the edge in Neo4j. The mapping does not use labels on nodes. >>> >>> I tested performance against the Fuseki >>> <https://jena.apache.org/documentation/serving_data/> Graphstore with >>> different sizes of datasets. Unfortunately the RDF mapping has its >>> drawbacks, because Neo4j needs much more space than Fuseki. The largest >>> dataset I tried was 17.9 GB in n-triples format. >>> Fuseki uses ~ 9 GB disk space after import, but Neo4j allocated 390 GB. >>> That also results in about 27 times slower query execution on this large >>> dataset. Using the smallest dataset with just 2 MB Neo4j is just 2.4 times >>> slower than Fuseki. I used the "Berlin SPARQL Benchmark >>> <http://wifo5-03.informatik.uni-mannheim.de/bizer/berlinsparqlbenchmark/>" >>> for testing. >>> >>> Do you have any examples for rdf / turtle import using the plugin? >>>> >>> Yes, on the GitHub >>> <https://github.com/niclashoyer/neo4j-sparql-extension#sparql-graph-protocol> >>> page there is an example for turtle import using curl. A PUT request to the >>> graph resource will replace all data in the graph: >>> >>> $ curl -v -X PUT \ >>> localhost:7474/rdf/graph \ >>> -H "Content-Type:text/turtle" --data-binary @data.ttl >>> >>> >>>> And if you had a blog post, we could help you promote the plugin and >>>> also link it from our website. >>>> >>> Yes, I don't have a blog post yet. I'll come back to you as soon as I've >>> got something. >>> >>> >>>> Where are you located? >>>> >>> Kiel, Germany. >>> >>> Regards, >>> Niclas >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Neo4j" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- > You received this message because you are subscribed to the Google Groups > "Neo4j" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Neo4j" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
