title: How do I unlock a tuple after updating in MySQL/Innodb?
body: <p>I am trying to model a transaction database for my databases course. I can't find how to unlock a tuple after using it for update.</p>
  
  <p>I have used commits and assumed that this would release the exclusive lock but it doesn't.</p>
  
  <pre class="lang-sql prettyprint-override"><code>START TRANSACTION;
  BEGIN;
  SELECT * FROM account WHERE account_num = 3 FOR UPDATE;
  UPDATE account SET balance= balance + 100 WHERE account_num = 3;
  COMMIT;
  </code></pre>
  
  <p>What am I supposed to do to make sure this exclusive lock is let go?</p>