title: Does Entity Framework's DbContext save changes if no changes were made?
body: <p>I could not find an answer on the Internet.</p>
  
  <p>Let's suppose I have a <code>DbContext</code>, and I just select all the entities from it. I don't add, update or delete any entity on the <code>DbSet</code>.</p>
  
  <p>If I call <code>SaveChanges</code> afterwards on the <code>DbSet</code>. Does it actually waste resources establishing a connection and other stuff even If I did not made any changes to the <code>DbSet</code>?</p>
  
  <p>Is it smart enough to detect if a change was made or not, and behave differently?</p>