assertion  retraction  graph  subject       predicate        object    datatype    annotation
1          0           graph  DOID:656      oio:id           DOID:656  xsd:string  
1          0           graph  DOID:0050891  rdfs:subClassOf  DOID:656  _IRI        
1          0           graph  DOID:12028    rdfs:subClassOf  DOID:656  _IRI