assertion  retraction  graph  subject    predicate        object    datatype    annotation
1          0           graph  DOID:6492  rdfs:subClassOf  DOID:476  _IRI        
1          0           graph  DOID:6491  rdfs:subClassOf  DOID:476  _IRI        
1          0           graph  DOID:476   oio:id           DOID:476  xsd:string