title: sqlite3 update statement in python returns lock error
body: <p>I am trying to update a sqlite3 database through iPython.
  I can succesfully insert data into the database, but when I try to update a row it returns the following error on me:</p>
  
  <pre><code>---------------------------------------------------------------------------
  OperationalError                          Traceback (most recent call last)
  &lt;ipython-input-160-6483798c376d&gt; in &lt;module&gt;()
        2 conn.text_factory = str
        3 conn.execute("update series set html='test123' where url='https://www.google.com/'")
  ----&gt; 4 conn.commit()
        5 print "Total number of rows updated :", conn.total_changes
  
  OperationalError: database is locked
  </code></pre>
  
  <p>The python code I used is the following.</p>
  
  <pre><code>conn = sqlite3.connect('mydb.db')
  conn.text_factory = str
  conn.execute("update series set html='test123' where url='https://www.google.com/'")
  conn.commit()
  print "Total number of rows updated :", conn.total_changes
  </code></pre>
  
  <p>What am I doing wrong?</p>