[web2py] Re: SQLFORM, DAL and Hidden Fields - a way or a better way?

[lyn2py]

Here's the code:

#model
db.define_table('discussion',
  Field('title', 'string', length=255, required=True),
  Field('description', 'text', required=True),
  Field('created_by', 'reference auth_user', default=auth.user_id,
writable=False, readable=False),
  Field('modified_by', 'reference auth_user', update=auth.user_id,
writable=False, readable=False),
  ...many more default=some_value, writable=False, readable=False
fields...
)

#controller
def create():
  form=SQLFORM(db.discussion)
  if form.process().accepted:
    response.flash = 'form accepted'
  elif form.errors:
    response.flash = 'form has errors'
  return dict(form=form)

###results
I get "Form Accepted" flashed when I fill in "title" and
"description", but fields "created_by" and "modified_by" are "None".

Thank you!