不需要字段

Guess your model is like this:

class My_Class(models.Model):


address = models.CharField()

Your form for Django version < 1.8:

class My_Form(ModelForm):


address = forms.CharField(required=False)


class Meta:
model = My_Class
fields = ('first_name', 'last_name' , 'address')

Your form for Django version > 1.8:

class My_Form(ModelForm):


address = forms.CharField(blank=True)


class Meta:
model = My_Class
fields = ('first_name', 'last_name' , 'address')

You would have to add:

address = forms.CharField(required=False)

class My_Form(forms.ModelForm):
class Meta:
model = My_Class
fields = ('first_name', 'last_name' , 'address')


def __init__(self, *args, **kwargs):
super(My_Form, self).__init__(*args, **kwargs)
self.fields['address'].required = False

@Anentropic's solution from the comment on @Atma's answer worked for me. And I think it's the best one too.

His comment:

null=True, blank=True will cause the ModelForm field to be required=False

I just set it on my ManyToMany field in my UserProfile class and it worked flawlessly.

My UserProfile class now looks like this (notice the friends field):

class UserProfile(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
friends = models.ManyToManyField('self', null=True, blank=True)

I also think that this is the most beautiful solution since you do the same thing, put null and blank to True, weather you have a simple char field or, like I have, ManyToMany field.

field = models.CharField(max_length=9, default='', blank=True)

Just add blank=True in your model field and it won't be required when you're using modelforms.

"If the model field has blank=True, then required is set to False on the form field. Otherwise, required=True."

source: https://docs.djangoproject.com/en/4.1/topics/forms/modelforms/#field-types

[Edit]: Change django doc link from 3.1 to 4.1

The above answers are correct; nevertheless due note that setting null=True on a ManyToManyField has no effect at the database level and will raise the following warning when migrating:

(fields.W340) null has no effect on ManyToManyField.

A good answer to this is explained in this other thread.

Solution: use both blank=True, null=True.

my_field = models.PositiveIntegerField(blank=True, null=True)

Explanation:

If you use null=True

my_field = models.PositiveIntegerField(null=True)

then my_field is required, with * next to it in the form and you can't submit the empty value.

If you use blank=True

my_field = models.PositiveIntegerField(blank=True)

then my_field is not required, there won't be a * next to it in the form and you can't submit the value. But it will get null field not allowed.

Note: marking as not required and allowing null fields are two different things.

Pro Tip: Read the error more carefully than documentation.