Django unique model fields validation in form

问题

I have a model with a few unique fields and I'm writing a form for it. I found some reference to the [validate_unique][1] method that should check for uniqueness on fields when you call it but my form .is_valid() always returns True.

My testcase:

class ServerFormTest( TestCase ):
    def setUp( self ):
        self.server = Server.objects.create( host = "127.0.0.1", name = "localhost" )

    def test_unique_name(self):
        form = ServerForm({
            'name': 'localhost',
            'host': '127.0.0.1'
        })

        self.assertFalse( form.is_valid( ) )

and my form:

class ServerForm( forms.ModelForm ):
    class Meta:
        model = Server
        fields = ('name', 'host')

    def clean( self ):
        self.validate_unique()
        return self.cleaned_data

server model:

class Server( models.Model ):
    host = models.GenericIPAddressField( blank = False, null = False, unique = True )
    name = models.CharField( blank = False, null = False, unique = True, max_length = 55 )

回答1:

validate_unique is a Model method.

Running the superclass clean method should take care of model uniqueness checks given a ModelForm.

class MyModelForm(forms.ModelForm):    
    def clean(self):
        cleaned_data = super(MyModelForm, self).clean()
        # additional cleaning here
        return cleaned_data

There is a warning on the django docs specifically about overriding clean on ModelForms, which automatically does several model validation steps.

回答2:

I solve it by adding validate_unique() to save()

class Server( models.Model ):
    host = models.GenericIPAddressField( blank = False, null = False, unique = True )
    name = models.CharField( blank = False, null = False, unique = True, max_length = 55 )

    def save(self, *args,**kwargs):
        self.validate_unique()
        super(Server,self).save(*args, **kwargs) 

It works for me. I don't know about you.

来源：https://stackoverflow.com/questions/31150929/django-unique-model-fields-validation-in-form