public function delete($id, $company = null)
 {
     $this->db->trans_start();
     $this->load->model("BookmarkModel");
     $this->load->model("ApplicationModel");
     # delete bookmark related by job
     $bookmark = new BookmarkModel();
     $bookmark->delete_by_job($id);
     # delete application related by job
     $application = new ApplicationModel();
     $application->delete_by_job($id);
     # remove the job itself
     $condition = array(JobModel::$primary_key => $id);
     if ($company != null) {
         $condition["job_company"] = $company;
     }
     $this->db->delete(JobModel::$table_name, $condition);
     $this->db->trans_complete();
     return $this->db->trans_status();
 }