assertion  retraction  graph  subject    predicate        object    datatype    annotation
1          0           graph  DOID:502   oio:id           DOID:502  xsd:string  
1          0           graph  DOID:7994  rdfs:subClassOf  DOID:502  _IRI        
1          0           graph  DOID:4055  rdfs:subClassOf  DOID:502  _IRI        
1          0           graph  DOID:5254  rdfs:subClassOf  DOID:502  _IRI