assertion  retraction  graph  subject    predicate        object     datatype    annotation
1          0           graph  DOID:2436  oio:id           DOID:2436  xsd:string  
1          0           graph  DOID:2435  rdfs:subClassOf  DOID:2436  _IRI        
1          0           graph  DOID:7996  rdfs:subClassOf  DOID:2436  _IRI