assertion  retraction  graph  subject    predicate        object     datatype    annotation
1          0           graph  DOID:6170  oio:id           DOID:6170  xsd:string  
1          0           graph  DOID:4115  rdfs:subClassOf  DOID:6170  _IRI        
1          0           graph  DOID:6445  rdfs:subClassOf  DOID:6170  _IRI