3x Magento Master
Coupon code used to get a discount from the order. Different types of coupons available for the eCommerce store like, only specific Item has a discount, a discount for the whole cart and so.
If you want to get coupon data by coupon code, You can retrieve the data of coupon by its code.
You can get applied rule ids of the product item from the Sales Order by order item id.
A customer has applied the shopping cart rule for the order and if any item contains that specific rules, after place order, the sales item persists the shopping cart rule id in the sales_order_item database table for the item level.
Shopping cart Coupon deletes by coupon id in Magento 2 to get rid of all the expired coupons from the site.
Many of the coupons are created for specific events or some special days only like Black Friday or Cyber Monday after completed that day.