title: Column default value persisted to the table
body: <p>I am currently using a <code>Column</code> that has the following signature:</p>
  
  <p><code>Column('my_column', DateTime, default=datetime.datetime.utcnow)</code></p>
  
  <p>I am trying to figure out how to change that in order to be able to do vanilla sql inserts (<code>INSERT INTO ...</code>) rather than through sqlalchemy. Basically I want to know how to persist the default on the table without lossing this functionality of setting the column to the current utc time.</p>
  
  <p>The database I am using is PostgreSQL.</p>