Is the scheme in 3rd normal form?
Order(OrderNo; Order Date; ↑Last Name; ↑First Name; ↑Registration Date; ↑Delivery No; ↑Product ID)
Customer (Name; First name; Registration date; Telephone number; Address; Email; House number)
Delivery (delivery number; delivery date, delivery service)
Product(ProductID; Name; Price, Rating, Brand)
Order: Is only one product possible per order?
If not, here is a table of order details added in which the order number, the product ID (and possibly quantity) is stored.
Order: First name and last name will probably be a composite key from the customer table. Question -> How do you picture it if two orders are received, where Klaus Müller from X wants to have a product and then Klaus Müller from Y will place his order? First name and last name are not sufficient for a clear identification of customers. And as it is intended to avoid the multiple storage of data: Why does the customer table have no ID field, which then serves as a reference in the orders to identify the customer?
Order: Delivery no…. does not belong here. In the table delivery, the reference to the order number belongs to the delivery details. When ordering, the delivery number is generally not known from the workflow.
@Xandros0506 has already delivered you a good answer.
As a supplement:
Delivery, the delivery service repeats and should therefore be strictly included in a separate table delivery services with id and name and then delivery service ID in the table delivery.
If we are currently at ID, I would recommend you not to use one ID and the other no. Stay uniform.