assertion  retraction  graph  subject    predicate        object     datatype    annotation
1          0           graph  DOID:1752  oio:id           DOID:1752  xsd:string  
1          0           graph  DOID:6037  rdfs:subClassOf  DOID:1752  _IRI        
1          0           graph  DOID:6992  rdfs:subClassOf  DOID:1752  _IRI