title: ER diagram for a bookstore
body: <p>I have a <code>book store application</code> and i want to design it's database. Then first of all i need to it's E-R diagram.</p>
  
  <p><code>(This is not homework)</code></p>
  
  <p>It has so simple Scenario:</p>
  
  <ul>
  <li><p>Every User can have 0 , 1 , or more book order.</p></li>
  <li><p>There is more than one instance of each type of book.</p></li>
  </ul>
  
  <p>Is this the best design?</p>
  
  <p><img src="https://i.stack.imgur.com/RSLOT.jpg" alt="enter image description here"></p>