Untitled

erDiagram
  entity Product {
    product_id: int PK
    name: varchar(255)
    price: decimal(10,2)
  }
  entity Transaction {
    transaction_id: int PK
    date: date
    time: time
    total_amount: decimal(10,2)
    cashier_id: int
  }
  entity Customer (optional) {
    customer_id: int PK
    name: varchar(255)
    contact_details: varchar(255)
  }

  Transaction --1:N--> Product
  Transaction --0:1--> Customer (optional)