title: Entity Relationship Diagram Sales
body: <p>I wanted to ask your opinion on the following ERD diagram i made. Keep in mind that i haven't already represented the cardinality of the relations yet.</p>
  
  <p><a href="https://i.imgur.com/pUyKHE7.png" rel="nofollow noreferrer"><img src="https://i.imgur.com/pUyKHE7.png" alt=""></a></p>
  
  <p>What i'm going for is:</p>
  
  <ul>
  <li>A client goes in to buy a car;</li>
  <li>The car can be upgraded with many extras which add up to the base price of the car;</li>
  <li>The salesman can offer extras at no cost or offer a discount on the sale's total price in order to captivate clients;</li>
  </ul>
  
  <p>What do you think of my diagram? Is it right? Do you see anything wrong?</p>
  
  <p><strong>[EDIT]</strong></p>
  
  <p>How do i go about representing the following scenario. A customer sells me a used car as a part of a purchase of a new car. </p>