Doctrine\DBAL\Connection::transactional PHP Method

    public function transactional(Closure $func)
    {
        $this->beginTransaction();
        try {
            $res = $func($this);
            $this->commit();
            return $res;
        } catch (Exception $e) {
            $this->rollBack();
            throw $e;
        } catch (Throwable $e) {
            $this->rollBack();
            throw $e;
        }
    }

 /**
  * @param string $endpointName
  *
  * @return int
  */
 public function fetchOrGenerateEndpointId($endpointName)
 {
     $endpointId = 0;
     $this->connection->transactional(function (Connection $connection) use($endpointName, &$endpointId) {
         $lookupHash = md5($endpointName);
         $endpointRecord = $connection->executeQuery("SELECT * FROM {$this->endpointsTableName} WHERE lookup_hash = ?", [hex2bin($lookupHash)])->fetch(\PDO::FETCH_ASSOC);
         if (!$endpointRecord) {
             $connection->insert($this->endpointsTableName, ['lookup_hash' => hex2bin($lookupHash), 'name' => $endpointName]);
             $endpointId = (int) $connection->lastInsertId();
         } else {
             $endpointId = (int) $endpointRecord['id'];
         }
     });
     return $endpointId;
 }