Cara memperbarui nilai tombol radio dalam database menggunakan PHP

<input type="radio" name="type" value="S" <?php if ($type == 'S') echo 'checked="checked"'; ?>" /> Student<br />
<input type="radio" name="type" value="T" <?php if ($type == 'T') echo 'checked="checked"'; ?>" /> Teacher<br />
Sleepy Squirrel