Is the word start a usable field name in a Django model?

Question

I have a model called Order with a datetime field called start. I can read and write from/to that field no problem.

However, I just created a ModelForm and specified start as one of the fields=() in Meta and I get:

Unknown field(s) (start) specified for Order

I've made sure it is not a typo by copying and pasting the field name. If I remove that field, it works.

Here is the exact ModelForm

class OrderForm(ModelForm):
    class Meta:
        model = Order
        fields = ('details', 'start', 'quantity', 'total')

EDIT added more details:

I tried using exclude = () to exclude all fields except those I need, and start does not appear in the form even though I don't exclude it.

Here is the model:

class Order(MyModel):
    user = models.ForeignKey(User, )
    invoice = models.ForeignKey(Invoice, )
    unit_price = models.DecimalField(max_digits=6, decimal_places=2, blank=True, null=True, )
    subtotal = models.DecimalField(max_digits=6, decimal_places=2, blank=True, null    =True, )
    tax = models.DecimalField(max_digits=6, decimal_places=2, blank=True, null=True, )
    misc = models.DecimalField(max_digits=5, decimal_places=2, blank=True, null=True, )
    total = models.DecimalField(max_digits=6, decimal_places=2, blank=True, null=True, )
    start = models.DateTimeField(auto_now_add=True, blank=True, null=True, )
    end = models.DateTimeField(editable=True, blank=True, null=True, )
    duration = models.PositiveSmallIntegerField(blank=True, null=True, )
    quantity = models.PositiveSmallIntegerField(blank=True, null=True, )
    notes = models.CharField(max_length=256, blank=True, null=True, )
    details = models.CharField(max_length=64, blank=True, null=True, )
    configured = models.BooleanField(default=False, )

Answer 1

I removed the auto_now_add=True and the problem is solved.

Thanks for everyone's help.

Answer 2

Remove:

auto_now_add=True

Model field reference | Django documentation | Django :

As currently implemented, setting auto_now or auto_now_add to True will cause the field to have editable=False and blank=True set.

Answer 3

Maybe you have editable=False defined for the start field?

According to documentation:

If False, the field will not be displayed in the admin or any other ModelForm. Default is True.