assertion  retraction  graph  subject    predicate        object     datatype    annotation
1          0           graph  DOID:5170  rdfs:subClassOf  DOID:1901  _IRI        
1          0           graph  DOID:1901  oio:id           DOID:1901  xsd:string  
1          0           graph  DOID:5283  rdfs:subClassOf  DOID:1901  _IRI