title: how can i use a string to to represent an sqlalchemy object attribute?
body: <p>I am writing a Flask application with SQLalchemy and WTForms.</p>
  
  <p>Trouble with database updates... I have many object table fields I am trying to update.</p>
  
  <p>so I started with this...</p>
  
  <pre><code># this works great but needs many lines of code
  event.evt_num = form.evt_num.data
  event.evt_name = form.evt_name.data
  event.evt_location = form.evt_location.data
  event.evt_address = form.evt_address.data
  event.evt_city = form.evt_city.data
  event.evt_state = form.evt_state.data
  ...
  </code></pre>
  
  <p>While the above snippet works, in reality it is huge.  So I would like to be smarter and iterate thru the attributes to update the database.  So I tried the following...</p>
  
  <pre><code>event_fields = ('evt_num', 'evt_name', 'evt_location', 'evt_address',
                      'evt_city', 'evt_state', 'evt_zip', 'evt_notes')
  
  for aa in event_fields:
      print "form data", getattr(form, aa).data  # prints posted form data
      print "db data", getattr(event, aa) # prints posted data from database
  
      if getattr(form, aa).data != getattr(event, aa):  # if form data shows a change
          setattr(event, aa, getattr(form, aa).data)    # update database does not work
          db_change = True
          session.flush()
          ...
  </code></pre>
  
  <p>This line doesnt work to update the database:</p>
  
  <pre><code>setattr(event, aa, getattr(form, aa).data)
  </code></pre>
  
  <p>I get this error "<strong>AttributeError: 'Event' object has no attribute 'aa'</strong> "</p>
  
  <p>Your help will be greatly appreciated.</p>