src/Phossa/Query/Statement/UtilityTrait.php
protected function isRaw($str)/*# : bool */
    {
        if (is_string($str)) {
            return (bool) preg_match('/[^0-9a-zA-Z\$_.]/', $str);
        } elseif (is_object($str) && $str instanceof RawInterface) {
            return true;
        }
        return false;
    }
protected function isRaw($str)/*# : bool */
    {
        if (is_string($str)) {
            return (bool) preg_match('/[^0-9a-zA-Z\$_.]/', $str);
        } elseif (is_object($str) && $str instanceof RawInterface) {
            return true;
        }
        return false;
    }
If $string contains any char other than '[0-9a-zA-Z$_.]', we consider
it is a raw string case

@param  string|object $str
@return bool
@access protected