Json::entries_relationship PHP Method

  protected function entries_relationship($entry_id, $field, $field_data)
  {
    if (is_null($this->entries_relationship_data))
    {
      $query = ee()->db->select('parent_id, child_id, field_id')
                       ->where_in('parent_id', $this->entries_entry_ids)
                       ->order_by('order', 'asc')
                       ->get('relationships');

      foreach ($query->result_array() as $row)
      {
        if ( ! isset($this->entries_relationship_data[$row['parent_id']]))
        {
          $this->entries_relationship_data[$row['parent_id']] = array();
        }

        if ( ! isset($this->entries_relationship_data[$row['parent_id']][$row['field_id']]))
        {
          $this->entries_relationship_data[$row['parent_id']][$row['field_id']] = array();
        }

        $this->entries_relationship_data[$row['parent_id']][$row['field_id']][] = (int) $row['child_id'];
      }

      $query->free_result();
    }

    if (isset($this->entries_relationship_data[$entry_id][$field['field_id']]))
    {
      return $this->entries_relationship_data[$entry_id][$field['field_id']];
    }

    return array();
  }