Property Graph Ontology Context

pgoContext.ttl

PREFIX prec: <http://bruy.at/prec#>
PREFIX pvar: <http://bruy.at/prec-trans#>
PREFIX pgo:  <http://ii.uwb.edu.pl/pgo#>
PREFIX ex:   <http://example.org/>
PREFIX rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#>

# A PREC Context to produce RDF graphs similar to the one produced by graphConv
# PREC: https://github.com/BruJu/PREC
# graphConv: https://github.com/domel/graphConv

# Usage:
# node prec.js data/movies_cypher_all.json path/to/this/pgoContext.ttl -f Neo4JCypher
# Tested on commit 2da9f5dd4a16ec5bac69905569d032ae5266ccc4

# Differences with the graphs produced by graphConv in our experiment:
# - Numeric values (year for example) are xsd:integer with PREC, xsd:string with
# graphConv. We think an xsd:integer representation is more accurate.
# - Labels are described with pgo:label with this PREC context, are exported as
# properties with graphConv. The "PGO: Describing Property Graphs in RDF"
# article, by Tomaszuk et al. gives an example where label are actually
# represented with pgo:label (in the same way as PREC does)
# We think these differences are due to our Neo4j to GraphML export

# -- Property Graph Ontology replication

ex:pgoNodeLabel a prec:NodeLabelModel ;
  prec:composedOf << pvar:node pgo:label pvar:label >> .

ex:pgoEdge a prec:EdgeModel ;
  prec:composedOf
    << pvar:edge pgo:startNode pvar:source        >> ,
    << pvar:edge pgo:endNode   pvar:destination   >> ,
    << pvar:edge pgo:label     pvar:label         >> ,
    << pvar:edge pvar:propertyPredicate pvar:propertyObject >> .

prec:Relationships prec:templatedBy ex:pgoEdge .
prec:NodeLabels    prec:templatedBy ex:pgoNodeLabel .

# -- Properties

prec:NodeProperties    prec:templatedBy ex:pgoNodeProperty .
ex:pgoNodeProperty a prec:PropertyModel ;
  prec:composedOf
    << pvar:entity       pgo:hasNodeProperty  pvar:propertyNode     >> ,
    << pvar:propertyNode pgo:key              pvar:label             >> ,
    << pvar:propertyNode pgo:value            pvar:propertyValue     >> ,
    << pvar:propertyNode a pgo:Property >> ,
    << pvar:propertyNode pvar:metaPropertyPredicate pvar:metaPropertyObject >> .


prec:RelationshipProperties    prec:templatedBy ex:pgoEdgeProperty .
ex:pgoEdgeProperty a prec:PropertyModel ;
  prec:composedOf
    << pvar:entity       pgo:hasEdgeProperty  pvar:propertyNode     >> ,
    << pvar:propertyNode pgo:key              pvar:label             >> ,
    << pvar:propertyNode pgo:value            pvar:propertyValue     >> ,
    << pvar:propertyNode a pgo:Property >> ,
    << pvar:propertyNode pvar:metaPropertyPredicate pvar:metaPropertyObject >> .


prec:MetaProperties    prec:templatedBy ex:pgoMetaProperty .
ex:pgoMetaProperty a prec:PropertyModel ;
  prec:composedOf
    << pvar:entity      pgo:hasProperty      pvar:propertyNode     >> ,
    << pvar:propertyNode pgo:key              pvar:label             >> ,
    << pvar:propertyNode pgo:value            pvar:propertyValue     >> ,
    << pvar:propertyNode a pgo:Property >> ,
    << pvar:propertyNode pvar:metaPropertyPredicate pvar:metaPropertyObject >> .

# ---- Produce the property graph node
# We extend the pgoEdge and pgoNodeLabel templates to add a triple between
# the pg instance and the node

# PREC is unable to apply a rule on unlabeled nodes, neither it can target
# isolated nodes only. In the current state, we produce a triple between the
# PG and the node for node that is either labeled or is connected to another
# node (or both).

ex:pgoEdge      prec:composedOf
  << _:thisPG pgo:hasEdge pvar:edge        >> ,
  << _:thisPG pgo:hasNode pvar:source      >> ,
  << _:thisPG pgo:hasNode pvar:destination >> ,
  << _:thisPG rdf:type pgo:PropertyGraph   >> .

ex:pgoNodeLabel prec:composedOf
  << _:thisPG pgo:hasNode pvar:node >> ,
  << _:thisPG rdf:type pgo:PropertyGraph >> .