title: Best way to do enum in Sqlalchemy?
body: <p>I'm reading about sqlalchemy and I saw following code:</p>
  
  <pre><code>employees_table = Table('employees', metadata,
      Column('employee_id', Integer, primary_key=True),
      Column('name', String(50)),
      Column('manager_data', String(50)),
      Column('engineer_info', String(50)),
      Column('type', String(20), nullable=False)
  )
  
  employee_mapper = mapper(Employee, employees_table, \
      polymorphic_on=employees_table.c.type, polymorphic_identity='employee')
  manager_mapper = mapper(Manager, inherits=employee_mapper, polymorphic_identity='manager')
  engineer_mapper = mapper(Engineer, inherits=employee_mapper, polymorphic_identity='engineer')
  </code></pre>
  
  <p>Should I make 'type' an int, with constants in a library?  Or should I make just make type an enum?</p>