assertion  retraction  graph  subject    predicate        object     datatype    annotation
1          0           graph  DOID:6179  oio:id           DOID:6179  xsd:string  
1          0           graph  DOID:7651  rdfs:subClassOf  DOID:6179  _IRI        
1          0           graph  DOID:7650  rdfs:subClassOf  DOID:6179  _IRI