Json::entries_rel PHP Method

  protected function entries_rel($entry_id, $field, $field_data)
  {
    if (is_null($this->entries_rel_data))
    {
      $query = ee()->db->select('rel_child_id, rel_id')
                       ->where('rel_parent_id', $entry_id)
                       ->get('relationships');

      $this->entries_rel_data = array();

      foreach ($query->result() as $row)
      {
        $this->entries_rel_data[$row->rel_id] = (int) $row->rel_child_id;
      }

      $query->free_result();
    }

    if ( ! isset($this->entries_rel_data[$field_data]))
    {
      return NULL;
    }

    return $this->entries_rel_data[$field_data];
  }