assertion  retraction  graph  subject    predicate        object     datatype    annotation
1          0           graph  DOID:6858  rdfs:subClassOf  DOID:6856  _IRI        
1          0           graph  DOID:6857  rdfs:subClassOf  DOID:6856  _IRI        
1          0           graph  DOID:6856  oio:id           DOID:6856  xsd:string