title: mixing placeholders, executemany, and table names
body: <p>I can iterate through a python object with te following code, however I would like to be able to use placeholders for the schema and table name, normally I do this with <code>{}.{}</code> ad the <code>.format()</code> methods, but how do you combine the two?</p>
  
  <pre><code>cur.executemany("INSERT INTO schema.table_name (x,y,z) "
                          "values (%s, %s, %s)", top_sample)
  </code></pre>