title: How to update a column in all rows of a table?
body: <p>I have the code:</p>
  
  <pre><code>def show_dolar_today(self):
  
      rate = self.get_dolar_today()
      self.env.cr.execute('update product_rate set rate=%s where id=%s', (rate,1))
  </code></pre>
  
  <p>the record with <code>id = 1</code> is updated in the table, but I want to update all the records that are in the table, how can I do that?</p>