title: What do the mysql workbench column icons mean in ER Diagram?
body: <p>Can any one help me in explaining about the icons in the ER Diagram of Database created in MySQL Workbench.</p>
  
  <p><img src="https://i.imgur.com/mAztpEr.jpg" alt="x" title="picture showing MySQL workbench interface"></p>
  
  <ul>
  <li>Blue Diamond (Filled);</li>
  <li>Blue Diamond (unfilled);</li>
  <li>Red Diamond, et cetera;<br>
  Thanks!</li>
  </ul>