assertion  retraction  graph  subject     predicate        object      datatype    annotation
1          0           graph  DOID:5628   rdfs:subClassOf  DOID:10020  _IRI        
1          0           graph  DOID:4932   rdfs:subClassOf  DOID:10020  _IRI        
1          0           graph  DOID:10020  oio:id           DOID:10020  xsd:string