neosemantics (n10s)

neosemantics is a plugin that enables the use of RDF in Neo4j. RDF is a W3C standard model for data interchange. Some key features of n10s are:

• Store RDF data in Neo4j in a lossless manner (imported RDF can subsequently be exported without losing a single triple in the process).
• On-demand export property graph data from Neo4j as RDF.
• Model validation based on the W3C SHACL language
• Import of Ontologies and Taxonomies in OWL/RDFS/SKOS/...

Other features in NSMNTX include model mapping and inferencing on Neo4j graphs.

⇨ User Manual and Blog ⇦

⇨ Check out the complete user manual with examples of use. ⇦

⇨ Blog on neosemantics (and more). ⇦

Installation

You can either download a prebuilt jar from the releases area or build it from the source. If you prefer to build, check the note below.

1. Copy the the jar(s) in the <NEO_HOME>/plugins directory of your Neo4j instance. (note: If you're going to use the JSON-LD serialisation format for RDF, you'll need to include also APOC)
2. Add the following line to your <NEO_HOME>/conf/neo4j.conf

dbms.unmanaged_extension_classes=n10s.endpoint=/rdf

3. Restart the server.
4. Check that the installation went well by: Running call dbms.procedures(). The list of procedures should include a number of them prefixed by n10s.

Checking that the logs show the following line on startup:

YYYY-MM-DD HH:MM:SS.000+0000 INFO  Mounted unmanaged extension [n10s.endpoint] at [/rdf]

You can also test the extension is mounted by running :get http://localhost:7474/rdf/ping on the neo4j browser and this should return the following message

{"ping":"here!"}

Basic flow

0. Pre-req: Constraint Creation

CREATE CONSTRAINT n10s_unique_uri ON (r:Resource) ASSERT r.uri IS UNIQUE

1. Creating a Graph Configuration

Before any RDF import operation a GraphConfig needs to be created. Here we define the way the RDF data is persisted in Neo4j. We'll find things like

Param	Values	Desc
handleVocabUris	"SHORTEN","KEEP","SHORTEN_STRICT","MAP"	how namespaces are handled
handleMultival	"OVERWRITE","ARRAY"	how multivalued properties are handled
handleRDFTypes	"LABELS","NODES","LABELS_AND_NODES"	how RDF datatypes are handled
multivalPropList	[ list of predicate uris ]
...	...	...

Most of them are the same (expect some changes) as in previous versions (see 3.5 manual for reference).

You can create a graph config with all the defaults like this:

call n10s.graphconfig.init()

Or customize it by passing a map with your options:

call n10s.graphconfig.init( { handleMultival: "ARRAY", 
                              multivalPropList: ["http://voc1.com#pred1", "http://voc1.com#pred2"],
                              keepLangTag: true })

2. Importing RDF data

Once the Graph config is created we can import data from a url using fetch:

call n10s.rdf.import.fetch( "https://raw.githubusercontent.com/jbarrasa/neosemantics/3.5/docs/rdf/nsmntx.ttl",
                            "Turtle")

Or pass it as a parameter using inline:

with '
@prefix neo4voc: <http://neo4j.org/vocab/sw#> .
@prefix neo4ind: <http://neo4j.org/ind#> .

neo4ind:nsmntx3502 neo4voc:name "NSMNTX" ;
			   a neo4voc:Neo4jPlugin ;
			   neo4voc:runsOn neo4ind:neo4j355 .

neo4ind:apoc3502 neo4voc:name "APOC" ;
			   a neo4voc:Neo4jPlugin ;		   
			   neo4voc:runsOn neo4ind:neo4j355 .

neo4ind:graphql3502 neo4voc:name "Neo4j-GraphQL" ;
			   a neo4voc:Neo4jPlugin ;			   
			   neo4voc:runsOn neo4ind:neo4j355 .			   			   

neo4ind:neo4j355 neo4voc:name "neo4j" ;
			   a neo4voc:GraphPlatform , neo4voc:AwesomePlatform .

' as  payload

call n10s.rdf.import.inline( payload, "Turtle") yield terminationStatus, triplesLoaded, triplesParsed, namespaces
return terminationStatus, triplesLoaded, triplesParsed, namespaces

It is possible to pass some request specific parameters like headerParams, commitSize, languageFilter... (also found in the 3.5 manual)

3. Importing Ontologies, QuadRDF, etc

Same naming scheme applies...

call n10s.onto.import.fetch(...)

Use autocompletion to discover the different procedures.

Full documentation will be available soon. In the meantime, please share your feedback in the Neo4j community portal.

Thanks!