Doctrine\DBAL\Driver\Mysqli\MysqliStatement::bindParam PHP Method

    public function bindParam($column, &$variable, $type = null, $length = null)
    {
        if (null === $type) {
            $type = 's';
        } else {
            if (isset(self::$_paramTypeMap[$type])) {
                $type = self::$_paramTypeMap[$type];
            } else {
                throw new MysqliException("Unknown type: '{$type}'");
            }
        }
        $this->_bindedValues[$column] =& $variable;
        $this->types[$column - 1] = $type;
        return true;
    }