Sigh-up模組欄位儲存與會員資料對應修改問題

請教版上前輩

我想增加Sigh-up模組的欄位，網路上看到可以從signup/theme/signup_form.inc內增加


function theme_signup_user_form($node) {
global $user;
$form = array();

// If this function is providing any extra fields at all, the following
// line is required for form form to work -- DO NOT EDIT OR REMOVE.
$form['signup_form_data']['#tree'] = TRUE;

$form['signup_form_data']['Name'] = array(
'#type' => 'textfield',
'#title' => t('Name'),
'#size' => 40, '#maxlength' => 64,
'#required' => TRUE,
);
$form['signup_form_data']['Phone'] = array(
'#type' => 'textfield',
'#title' => t('Phone'),
'#size' => 40, '#maxlength' => 64,
);

// If the user is logged in, fill in their name by default.
if ($user->uid) {
$form['signup_form_data']['Name']['#default_value'] = $user->name;
}

return $form;
}

不過我想了解我增加的欄位值會被儲存在資料庫嗎？因為找了signup模組其他檔案似乎都沒有發現Phone欄位儲存內容，推測是不是後續所增加的欄位都全部組成一個內容去儲存？

另外，drupal預設會員註冊時只有帳號跟密碼，若我也想類似這樣的作法增加欄位，該如何做呢？