When Django models field is empty, set value to the Default value

Question

Whenever the user doesn't add a value, I need my Django models to replace the otherwise empty field with the value set in default.
My models looks like this:

not_before = models.TimeField(blank=True, null=True, default='00:00:00')
max_num_per_day = models.IntegerField(blank=True, null=True, default=0)

I tried every combination of null, blank and default but no matter what I do, the fields gets replaced by null instead of '00:00:00' and 0.

Is there anyway I can force it to the default value whenever the field is empty?

Answer 1

you can set up your form with a default function like:

class YourForm(forms.Form):    
.....
def clean_field(self):
        data = self.cleaned_data['not_before']
        if not data:
            data = '00:00:00'

or write a function in your model like:

class Molde(models.Model):
  not_before = models.TimeField(blank=True, null=True, default='00:00:00')
  def time(self):
    if self.not_before:
        return self.not_before
    else:
        return '00:00:00'

In this case you would call the function instead of the model field itself. You can also take a look at this.

Hope that helps.