assertion  retraction  graph  subject    predicate        object    datatype    annotation
1          0           graph  DOID:8472  rdfs:subClassOf  DOID:419  _IRI        
1          0           graph  DOID:419   oio:id           DOID:419  xsd:string  
1          0           graph  DOID:418   rdfs:subClassOf  DOID:419  _IRI