Django validate one model field against another in admin
django, python, validation
Solution
from django import forms
from django.contrib import admin
from .models import Tourney
class TourneyAdminForm(forms.ModelForm):
class Meta:
model = Tourney
fields = '__all__'
def clean(self):
if self.cleaned_data['registration_deadline'] > self.cleaned_data['start_date']:
raise forms.ValidationError('Registration deadline must be before the start date')
return self.cleaned_data
class TourneyAdmin(admin.ModelAdmin):
form = TourneyAdminForm
admin.site.register(Tourney, TourneyAdmin)
Problem
Say a model has two DateTimeFields: ``` class Tourney(models.Model): registration_deadline = models.DateTimeField() start_date = models.DateTimeField() ``` When a user tries to submit a Tourney from within the Django admin, how can I test that `registration_deadline` is before `start_date` before saving to the database and, if there is an error, of course inform the user inline, just as Django would if there were any OTHER validation errors? Basically, I'm looking for custom admin validation.This part of the Django docs is close, but seems to be for forms. How can I do the 'Cleaning and validating fields that depend on each other' from within Django's admin? Even just a pointer to the right place in the docs would be sufficient. Edit: I'm thinking it has something to do with validators, but they seem only able to test a single value, not two at the same time...