private function logNumberOfConstants(): void
  {
    $n_id  = sizeof($this->labels);
    $n_len = sizeof($this->constants) - $n_id;

    $this->io->writeln('');
    $this->io->text(sprintf('Number of constants based on column widths: %d', $n_len));
    $this->io->text(sprintf('Number of constants based on database IDs : %d', $n_id));
  }