rdflib-orm

A Python ORM for working with RDF. Note, this is experimental software not suited for production, yet.

Usage

from rdflib import Graph
from rdflib.namespace import DCTERMS, SKOS, OWL, DCAT, RDFS, RDF

from rdflib_orm.db import Database
from rdflib_orm import models


class Common(models.Model):
   provenance = models.CharField(predicate=DCTERMS.provenance, lang='en', required=True)

   class Meta:
       mixin = True


class ConceptScheme(Common):
   class_type = models.IRIField(predicate=RDF.type, value=SKOS.ConceptScheme)
   title = models.CharField(predicate=DCTERMS.title, lang='en', required=True)
   description = models.CharField(predicate=SKOS.definition, lang='en', required=True)
   created = models.DateTimeField(DCTERMS.created, auto_now_add=True)
   modified = models.DateTimeField(DCTERMS.modified, auto_now=True)
   creator = models.IRIField(predicate=DCTERMS.creator, required=True)
   publisher = models.IRIField(predicate=DCTERMS.publisher, required=True)
   version = models.CharField(predicate=OWL.versionInfo, required=True)
   custodian = models.CharField(predicate=DCAT.contactPoint)
   see_also = models.IRIField(predicate=RDFS.seeAlso, many=True)

   def __repr__(self):
       return f'<{self.__uri__}>'


class Concept(Common):
   class_type = models.IRIField(predicate=RDF.type, value=SKOS.Concept)
   pref_label = models.CharField(predicate=SKOS.prefLabel, lang='en', required=True)
   alt_labels = models.CharField(predicate=SKOS.altLabel, lang='en', many=True)
   definition = models.CharField(predicate=SKOS.definition, lang='en', required=True)
   children = models.IRIField(predicate=SKOS.narrower, many=True, inverse=SKOS.broader)
   other_ids = models.CharField(predicate=SKOS.notation, many=True)
   home_vocab_uri = models.IRIField(predicate=RDFS.isDefinedBy)

   def __repr__(self):
       return f'<{self.__uri__}>'


if __name__ == '__main__':
   g = Graph()
   g.bind('dcterms', DCTERMS)
   g.bind('skos', SKOS)
   g.bind('dcat', DCAT)
   g.bind('owl', OWL)
   Database.set_db(g, base_uri='http://example.com/')

   concept_scheme = ConceptScheme(
       'https://linked.data.gov.au/def/concept_scheme',
       title='A concept scheme',
       description='A description of this concept scheme.',
       creator='https://linked.data.gov.au/org/cgi',  # Accepts a URIRef or a string since the field is an IRIField.
       publisher='https://linked.data.gov.au/org/ga',
       version='0.1.0',
       provenance='Generated using Python',
       custodian='A custodian name',
       see_also=['http://example.com', 'http://another.example.com']  # Accepts a Python list since Field's many=True
   )

   concept_scheme.save()  # Save to store - currently memory store, but works also for remote triplestore.

   concept_scheme.title = 'Modified concept scheme title'
   concept_scheme.save()  # Save changes - we changed the title field.

   concept_a = Concept(
       uri='https://linked.data.gov.au/def/concept_a',
       pref_label='A concept',
       alt_labels=['An alt label', 'another alt label'],
       definition='Definition of this concept.',
       # children=  # Optional field, no children on this concept.
       other_ids=['123', '456'],  # No language tag here :)
       home_vocab_uri=concept_scheme,  # Reference the Concept Scheme Python object directly.
       provenance = 'Generated using RDFLib',
   )

   concept_a.save()

   concept_b = Concept(
       uri='https://linked.data.gov.au/def/concept_b',
       pref_label='Another concept',
       # alt_labels=  # Alt labels are optional.
       definition='Definition is not optional.',
       children=[concept_a],  # Reference the previous concept Python object directly. Notice it will also add the inverse property :)
       # other_ids=  # Optional field again.
       home_vocab_uri=concept_scheme,
       provenance='Generated using rdflib-orm',
   )

   concept_b.save()

   # Let's do some queries.
   queryset = Concept.objects.all()
   print(queryset)
   # <QuerySet [<https://linked.data.gov.au/def/concept_b>, <https://linked.data.gov.au/def/concept_a>]>

   # Get object by URI.
   concept_result = Concept.objects.get('https://linked.data.gov.au/def/concept_a')
   print(concept_result)
   # <https://linked.data.gov.au/def/concept_a>
   print(concept_result.pref_label)
   # A concept
   print(concept_result.definition)
   # Definition of this concept.

   # Not implemented yet. Something planned for the future.
   # Get object by any property, e.g. notation.
   # concept_result = Concept.objects.get(other_ids=123)

   print(len(g))  # 28 triples

   g.serialize('output.ttl', format='turtle')
   """ # Output of Graph.serialize()
@prefix dcat: <http://www.w3.org/ns/dcat#> .
@prefix dcterms: <http://purl.org/dc/terms/> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix skos: <http://www.w3.org/2004/02/skos/core#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

<https://linked.data.gov.au/def/concept_a> a skos:Concept ;
   dcterms:provenance "Generated using RDFLib"@en ;
   rdfs:isDefinedBy <https://linked.data.gov.au/def/concept_scheme> ;
   skos:altLabel "An alt label",
       "another alt label" ;
   skos:broader <https://linked.data.gov.au/def/concept_b> ;
   skos:definition "Definition of this concept."@en ;
   skos:notation "123",
       "456" ;
   skos:prefLabel "A concept"@en .

<https://linked.data.gov.au/def/concept_b> a skos:Concept ;
   dcterms:provenance "Generated using rdflib-orm"@en ;
   rdfs:isDefinedBy <https://linked.data.gov.au/def/concept_scheme> ;
   skos:definition "Definition is not optional."@en ;
   skos:narrower <https://linked.data.gov.au/def/concept_a> ;
   skos:prefLabel "Another concept"@en .

<https://linked.data.gov.au/def/concept_scheme> a skos:ConceptScheme ;
   dcterms:created "2021-05-26T22:13:50.720468"^^xsd:dateTime ;
   dcterms:creator <https://linked.data.gov.au/org/cgi> ;
   dcterms:modified "2021-05-26T22:13:50.723468"^^xsd:dateTime ;
   dcterms:provenance "Generated using Python"@en ;
   dcterms:publisher <https://linked.data.gov.au/org/ga> ;
   dcterms:title "Modified concept scheme title"@en ;
   rdfs:seeAlso <http://another.example.com>,
       <http://example.com> ;
   owl:versionInfo "0.1.0" ;
   skos:definition "A description of this concept scheme."@en ;
   dcat:contactPoint "A custodian name" .
   """

Running tests

pytest --cov=rdflib_orm --cov-report html

License

edmondchuc/rdflib-orm

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