assertion  retraction  graph  subject    predicate        object     datatype    annotation
1          0           graph  DOID:2468  rdfs:subClassOf  DOID:1561  _IRI        
1          0           graph  DOID:3324  rdfs:subClassOf  DOID:1561  _IRI        
1          0           graph  DOID:1561  oio:id           DOID:1561  xsd:string