[web2py] global name 'db' is not defined

[Роман Акимов]

Hello all!
Please help me.
I'm write:

model
db.define_table(
    'document_body',
    Field('name'),
    Field('number'),
    Field('created', 'datetime', default=request.now),
    Field('start_date', 'date'),
    Field('end_date', 'date'),
    Field('activity', 'boolean', default=True),
    )

controller
def index():
    form = SQLFORM(db.document_body)
    if form.process().accepted:
        response.flash = 'document uploaded'
    return dict(form = form)

And i have error in default.py:
<type 'exceptions.NameError'> global name 'db' is not defined

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