class Table extends Relation implements Iterable<Row> {

  @Override
  public int rowCount() {
    int result = 0;
    if (!columnList.isEmpty()) {
      // all the columns have the same number of elements, so we can check any of them
      result = columnList.get(0).size();
    }
    return result;
  }

  private  Table();
  private  Table(String name);
  protected  Table(String name, Column<?>... columns);
  protected  Table(String name, Collection<Column<?>> columns);

}