When Django models field is empty, set the value to default
Whenever the user doesn't add a value, I need my Django models to replace an otherwise empty field with the value set to default
.
My models look 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've tried every combination of null
, blank
and default
, but no matter what I do, the fields are replaced with null
instead of '00:00:00'
and 0
.
default
Is there anyway I can force its value whenever the field is empty?
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from what I understood from your question, you just want to set it as default. you can use: https://code.djangoproject.com/ticket/6754
not
not_before = models.TimeField(blank=True, null=True, default='00:00:00')
instead
import datetime not_before = models.TimeField(default=datetime.time(0,0)) max_num_per_day = models.IntegerField(default=0)
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you can customize your form with the 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 are calling the function instead of the model field itself. You can also take a look at.
Hope it helps.
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You seem to be using ModelForm to grab data from the user.
In this case, Sasuke's solution won't work. First, you need to set the parameter required
to False
in the form fields so that you stop sending "This field is required" messages. However, you will see errors when you save the form. Even if your model instance is initialized with a default value, the form will replace it with None
because there is an existing field in the form corresponding to the field in the model, and its value is None
.
My solution is to override the values in the model instance before storing them:
model_instance = myform.save(commit=False)
if not model_instance.not_before:
model_instance.not_before = '00:00:00'
if not model_instance.max_num_per_day:
model_instance.max_num_per_day = 0
model_instance.save()
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