Django Unique Together (with foreign keys)

Question

I have a situation where I want to use the Meta options of unique_together to enforce a certain rule, here\'s the intermediary model:

Answer 1

My 2 cents, complementing the accepted response from @Wolph

You can add validation for it yourself though, simply overwrite the validate_unique method and add this validation to it.

This is a working example code someone could find usefull.

from django.core.exceptions import ValidationError


class MyModel(models.Model):

    fk = models.ForeignKey(AnotherModel, on_delete=models.CASCADE)

    my_field = models.CharField(...)  # whatever

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

        if self.__class__.objects.\
                filter(fk=self.fk, my_field=self.my_field).\
                exists():
            raise ValidationError(
                message='MyModel with this (fk, my_field) already exists.',
                code='unique_together',
            )