assertion  retraction  graph  subject    predicate        object     datatype    annotation
1          0           graph  DOID:769   rdfs:subClassOf  DOID:2621  _IRI        
1          0           graph  DOID:2621  oio:id           DOID:2621  xsd:string  
1          0           graph  DOID:3201  rdfs:subClassOf  DOID:2621  _IRI