title: Does an enum in MySQL need to be NOT NULL?
body: <p>Lets say I have this:</p>
  
  <pre><code>ALTER TABLE asdf ADD field ENUM('Y', 'N') DEFAULT 'N';
  </code></pre>
  
  <p>Is putting a NOT NULL on the end necessary as it can only be Y and N?</p>
  
  <p>EDT: based on comments, if I know the software always sets it to 'N' or 'Y' and is hardcoded in then is it OK to leave it off or could it still potentially become null some how.</p>