assertion  retraction  graph  subject    predicate        object    datatype    annotation
1          0           graph  DOID:3308  rdfs:subClassOf  DOID:688  _IRI        
1          0           graph  DOID:688   oio:id           DOID:688  xsd:string  
1          0           graph  DOID:4766  rdfs:subClassOf  DOID:688  _IRI