title: Data Modeling: Supertype / Subtype
body: <p>Looking to figure out the proper way to model the below requirements.</p>
  
  <ol>
  <li>There are 3 types of “parties” to be concerned with, a Fan, a Band, and a BandMember.  </li>
  <li>That BandMember will always be associated with a Band and can also be a Fan of any band.  </li>
  <li>There are common attributes between a Fan, a Band, and a BandMember, but each of these 3 will also have their own unique attributes.</li>
  <li>A Fan can be a fan of of any Band or none at all</li>
  </ol>
  
  <p>This is a small part of a bigger thought but it is creating confusion in expanding the model.  I believe it would have to be diagram 2 or some other option since I don't see how a BandMember can be associated with a Band in the first model.</p>
  
  <p>I appreciate any input.</p>
  
  <p><img src="https://i.stack.imgur.com/DhGWT.png" alt="alt text"></p>
  
  <p><img src="https://i.stack.imgur.com/okEIx.png" alt="alt text"></p>