assertion  retraction  graph  subject    predicate        object     datatype    annotation
1          0           graph  DOID:3500  oio:id           DOID:3500  xsd:string  
1          0           graph  DOID:3499  rdfs:subClassOf  DOID:3500  _IRI        
1          0           graph  DOID:7222  rdfs:subClassOf  DOID:3500  _IRI