Magento - get rule from coupon code

Question

I have to retrieve the rule associated to a coupon code in order to display in quote the discount percentage of that rule. the simplest way is to calculate directly from quo

Answer 1

First get the coupon code

$orderNumber = 100000105; //order number with coupon code

$order = Mage::getModel('sales/order')->loadByIncrementId($orderNumber);

$orderDetails = $order->getData();

$couponCode = $orderDetails['coupon_code'];

Then use solution by Jürgen Thelen.