Untitled

```mermaid
erDiagram

  Customer -->|has| Order
  Customer -->|has many| OrderItem
  Order -->|has many| OrderItem
  OrderItem -->|belongs to| Product
  Product -->|has many| OrderItem
  Product -->|belongs to| Category
  Category -->|has many| Product
  
  Customer -->|has| User
  PromoCode -->|has many| User
  PromoCode -->|has many| Product
  ProductGroup -->|has many| Product
  UserRole -->|has many| User
  Customer -->|has many| Motorcycle
  Customer -->|has many| GiftCard
  GiftCard -->|has many| Order
  Customer -->|has many| ShoppingCart
  ShoppingCart -->|has many| Product
  Order -->|has many| OrderPaymentHistory
  OrderPaymentHistory -->|belongs to| Order
  Customer -->|has many| CustomerDocuments
  CustomerDocuments -->|belongs to| Customer
  
  Order -->|belongs to| Invoice
  Invoice -->|belongs to| Order
  
  class Customer {
    +id
    +name
    +email
    +password
    +address
  }
  
  class User {
    +id
    +username
    +password
    +role
    +customer_id
  }
  
  class Product {
    +id
    +name
    +price
    +description
    +image
    +category_id
  }
  
  class Category {
    +id
    +name
    +description
  }
  
  class ProductGroup {
    +id
    +name
    +description
  }
  
  class Order {
    +id
    +customer_id
    +order_date
    +total
  }
  
  class OrderItem {
    +id
    +order_id
    +product_id
    +quantity
  }
  
  class Invoice {
    +id
    +order_id
    +invoice_date
    +total
  }
  
  class PromoCode {
    +id
    +code
    +discount
    +start_date
    +end_date
    +is_single_use
  }
  
  class UserRole {
    +id
    +name
  }
  
  class GiftCard {
    +id
    +balance
    +start_date
    +end_date
  }
  
  class Motorcycle {
    +id
    +make
    +model
    +customer_id
  }
  
  class ShoppingCart {
    +id
    +customer_id
    +total
  }
  
  class OrderPaymentHistory {
    +id
    +order_id
    +payment_date
    +amount
  }
  
  class CustomerDocuments {
    +id
    +customer_id
    +file
  }

```