assertion  retraction  graph  subject    predicate        object     datatype    annotation
1          0           graph  DOID:2658  rdfs:subClassOf  DOID:2660  _IRI        
1          0           graph  DOID:2660  oio:id           DOID:2660  xsd:string  
1          0           graph  DOID:7079  rdfs:subClassOf  DOID:2660  _IRI