check if django model fields changed after save

django_field_update_checker.txt

class DjangoModel(models.Model):

    @classmethod
    def from_db(cls, db, field_names, values):
        instance = super().from_db(db, field_names, values)
        instance._state.adding = False
        instance._state.db = db
        instance._old_values = dict(zip(field_names, values))
        return instance
        
        
    def data_changed(self, fields):
        """
        example:
        if self.data_changed(['street', 'street_no', 'zip_code', 'city', 'country']):
            print("one of the fields changed")
            
        returns true if the model saved the first time and _old_values doesnt exist
       
        :param fields:
        :return:
        """
        if hasattr(self, '_old_values'):
            if not self.pk or not self._old_values:
                return True

            for field in fields:
                if getattr(self, field) != self._old_values[field]:
                    return True
            return False

        return True

Hi! Nice gist, thanks for creating it! I just noticed that the return False statement on line 31 is wrongly indented. It returns right after the first field is checked. I would also use self.pk instead of self.id since that is more general.

Yes, very nice, thanks. I also noticed the class def is wrong:

def DjangoModel(models.Model):

should be

class DjangoModel(models.Model):

Thank you. I updated the code.

Thank you! It was a salvation for me.

Very helpful, thank you!

Thank you!

thanks