Doctrine\DBAL\Query\QueryBuilder::execute PHP Method

    public function execute()
    {
        if ($this->type == self::SELECT) {
            return $this->connection->executeQuery($this->getSQL(), $this->params, $this->paramTypes);
        } else {
            return $this->connection->executeUpdate($this->getSQL(), $this->params, $this->paramTypes);
        }
    }

 /**
  * @return array
  */
 public function fetch()
 {
     $data = $this->query->execute()->fetchAll(\PDO::FETCH_KEY_PAIR);
     $keys = array_keys($data);
     $this->query->setParameter(':lastId', array_pop($keys));
     return array_values($data);
 }