大车? 需要订购和订购详情吗?

I have made a cart system that will show only the products where customers add to purchase, i mean they would just calculate the quantity and the total price of all products.

I wanted to ask if it is necessary for me to add an order and orderdetails table in my database?i just dont want to include the cart in my ERD

cart productNum quantity

order orderNum(PK) orderdate customerNum cardNum

orderdetails id(PK) orderNum(FK) productNum(FK) numOrdered quotedPrice amount

can someone explaint to me briefly what im going to do, need some suggestions

PS. please dont correct me if i have mistakes on my idea, im still a student who wants to learn more from someone who is willing to teach me