title: Can SQLAlchemy cache updates
body: <p>I would like to use SQLalchemy to update rows in a potentially large table using the ORM interface. But im not clear about something.</p>
  
  <p>My question is, assuming I have one session doing repeated selects and some updates, are these updates happening in the database or are they sometimes buffered in some ORM cache object?</p>
  
  <p>For example, If I'm repeating a select with a session which yields 10 rows like this:</p>
  
  <pre><code>session.query('User').filter(User.val == 42, User.surname == 'Dent')
  </code></pre>
  
  <p>.. but I only update the last row of that 10, </p>
  
  <ol>
  <li>Will the ORM always fetch the same 10 rows from DB or will it use cached values?</li>
  <li>will any caching behavior change with transaction markers?</li>
  </ol>