assertion  retraction  graph  subject    predicate        object     datatype    annotation
1          0           graph  DOID:6259  rdfs:subClassOf  DOID:6257  _IRI        
1          0           graph  DOID:6258  rdfs:subClassOf  DOID:6257  _IRI        
1          0           graph  DOID:6257  oio:id           DOID:6257  xsd:string