title: Can you replace or update a SQL constraint?
body: <p>I have written the following constraint for a column I've called 'grade':</p>
  
  <pre><code>CONSTRAINT gradeRule CHECK grade IN (‘easy’, ‘moderate’, ‘difficult’),
  </code></pre>
  
  <p>Is it possible to later update the <code>gradeRule</code> to have different values? For example, 'moderate' and 'difficult' could be changed to 'medium' and 'hard'.</p>
  
  <p>Thanks</p>