title: Why the need to commit explicitly when doing an UPDATE?
body: <p>Here's my code:</p>
  
  <pre><code>import cx_Oracle
  
  conn = cx_Oracle.connect(usr, pwd, url)
  cursor = conn.cursor()
  cursor.execute("UPDATE SO SET STATUS='PE' WHERE ID='100'")
  conn.commit()
  </code></pre>
  
  <p>If I remove the <code>conn.commit()</code>, the table isn't updated. But for select statements, I don't need that <code>conn.commit()</code>. I'm curious why?</p>