Django CreateView and validation

I am trying to implement shared views in my Django 1.8 application so that Django can take care of the validation / redirect loop for me.

I created a model:

class Customer(models.Model):
    custid = models.CharField(max_length=4, verbose_name='CID (4 alphanumeric uppercase)', validators=[validators.CIDValidator])
    customer_shortcode = models.CharField(max_length=7, verbose_name='Customer Code (7 chars, uppercase, no spaces)', validators=[validators.ShortnameValidator])
    description = models.CharField(max_length=30, blank=True)

      

        
        
        
      

    

and defined a validator for each of my two approved fields:

class CIDValidator(RegexValidator):
    regex = r'^[A-Z0-9]{4}$'
    message = 'CID is a 4-character uppercase alphanumeric value'

class ShortnameValidator(RegexValidator):
    regex = r'^[A-Z0-9_]{1,7}$'
    message = 'Shortname should be uppercase, no spaces, alphanumeric'

      

        
        
        
      

    

(At this point, I expected the admin interface to use validators when adding a Client, but this is not the case)

For a real application, I created a ModelForm for the Customer class:

class CustomerForm(ModelForm):

    class Meta:
            model = Customer
            fields = ['custid', 'customer_shortcode', 'description']

      

        
        
        
      

    

and the View class inherited from CreateView:

class CustomerCreateView(CreateView):
    model = Customer
    form_class = CustomerForm

    def get_success_url(self):
        return reverse('customer_list')

      

        
        
        
      

    

And I still don't get validation errors when entering invalid data in the generated form.

As far as I can follow from the docs, I only need to override clean () or clean_xxx () in the ModelForm for additional validation, but not for that, but this is really unclear. I would like to keep the information about what the valid value is in as few places as possible, which is what the validator on the ModelField does.

What's missing here? I suspect I am confused between model validation and form validation ...