title: Determing correct key values for multiple MySQL tables
body: <p>I am trying to determine how the tables need to be linked in which ways.</p>
  
  <p>The employees tables is directly linked to a number of tables which provide more information. A few of those tables have even more details. </p>
  
  <ul>
  <li>Employees have a unique <strong>employeeid</strong> <strike>but I understand best practice is to still have a id?</strike></li>
  <li>Customers have a unique <strong>customerid</strong></li>
  <li>Employees have a manager</li>
  <li>Managers are employees</li>
  <li>Customers have a <strike>manager associated with them.</strike> manager associated with them</li>
  <li>Employees may have a academic, certification and/or professional information.</li>
  </ul>
  
  <p>With all of this said what would be the best recommendation for creating primary and foreign keys? Is there a better way to handle the design?</p>
  
  <p><img src="https://i.stack.imgur.com/iG4OW.png" alt="Version2"></p>
  
  <hr>
  
  <p><strong>EDIT</strong></p>
  
  <p>Updated diagram to reflect feedback thus far. See comments to understand changes taking place.</p>
  
  <p><img src="https://i.stack.imgur.com/iefIz.png" alt="v3schema"></p>