title: How do I specify unique constraint for multiple columns in MySQL?
body: <p>I have a table:</p>
  
  <pre><code>table votes (
      id,
      user,
      email,
      address,
      primary key(id),
  );
  </code></pre>
  
  <p>Now I want to make the columns <strong>user, email, address</strong> unique (together).</p>
  
  <p>How do I do this in MySql?</p>
  
  <p>Of course the example is just... an example. So please don't worry about the semantics.</p>