assertion  retraction  graph  subject   predicate        object    datatype    annotation
1          0           graph  DOID:117  rdfs:subClassOf  DOID:176  _IRI        
1          0           graph  DOID:176  oio:id           DOID:176  xsd:string  
1          0           graph  DOID:175  rdfs:subClassOf  DOID:176  _IRI