php生成唯一id

public function getid(){
        $rand = rand(0, 999);
        do {
            if ($rand == 999) {
                $rand = 0;
            }
            $id = 'ID' .date('ymdHi'). $rand;
            $row = DB::where('id', $id)->first();
            $rand++;
        } while ($row);
        return $id;
    }