code: public DataNode createDataNode(IntermediateQueryFactory iqFactory, DataAtom dataAtom,
                                            Collection<Predicate> tablePredicates) {
  
          if (tablePredicates.contains(dataAtom.getPredicate())) {
              return iqFactory.createExtensionalDataNode(dataAtom);
          }
  
          return iqFactory.createIntensionalDataNode(dataAtom);
      }
docs: TODO: explain