assertion  retraction  graph  subject    predicate        object     datatype    annotation
1          0           graph  DOID:4916  oio:id           DOID:4916  xsd:string  
1          0           graph  DOID:4915  rdfs:subClassOf  DOID:4916  _IRI        
1          0           graph  DOID:5396  rdfs:subClassOf  DOID:4916  _IRI