how to have "city" fields depending on "country" field in Django models, without creating their tables

Question

I know there are several questions asked like this (such as this one), but non of them could help me with my problem.

I wanna have a City and a Country field in my models, which the City choices is depended on Country; BUT I do not want to define City and Country as models classes. here is my code :

from django.contrib.auth.models import User
from django.db import models
from django.forms import ChoiceField
from django_countries.fields import CountryField


class UserProfile(models.Model):
    user = models.OneToOneField(User, related_name="UserProfile")
    name = models.CharField(max_length=30, null=False, blank=False)
    picture = models.ImageField(upload_to='userProfiles/', null=False, blank=False)
    date_of_birth = models.DateTimeField(null=False, blank=False)
    country = CountryField()
    # city = ??
    national_code = models.IntegerField(max_length=10, null=False, blank=False)
    email = models.EmailField()

    def __str__(self):
        return '{}'.format(self.user.username)

    def __unicode__(self):
        return self.user.username

just like field "country" which is country = CountryField(), I wonder if there is a way that I could do the mission without defining the class Country(models.Model) or class City(models.Model)

Antitrust

you want to have city and country fields in your model but you dont want to define them? :) even from django_countries.fields import CountryField creates field, so how do you want to save data without a field in database? – Dudley

@Dudley - no i mean I want to have city and country fields in a model, but not to define a whole table for City or/and Country; because I don't need them and I just wanna have them as a field of my 'UserProfile' model – Antitrust

Answer 1

In order to do this you can use django-cities.

However, this will not resolve the issue with the input logic - if you need something like filtering the cities after selecting a country in your forms. You could use django-smart-selects for this but I am not sure how easy it is to implement the complex model structure of django-cities.

Sauerkraut

@far did you succeed ?? – Drizzle

This isn't really answering the question though is it? The question asks without defining a Country model and the django-cities does just that. – Bedaub

Answer 2

the only way for it would be to define choices in your model:

class UserProfile(models.Model):
    CITIES = (
        ('ny', 'New York'),
        ('sm', 'Santa Monica')
        # .. etc
    )
    city = models.CharField(max_length=5, choices=CITIES, blank=True)

more in the docs

Dudley

Answer 3

I had the same problem and I used django-cities-light to populate the city and regions/countries and django-smart-selects for filtering the resulting code was like this and worked well in the admin and in forms:

from django.db import models
from cities_light.models import City
from cities_light.models import Region
from smart_selects.db_fields import ChainedForeignKey

class Address(models.Model):
    ....
    state = models.ForeignKey(Region, on_delete=models.CASCADE)
    city = ChainedForeignKey(City, chained_field="state", chained_model_field="region")

Remember to add 'cities_light' and 'smart_selects' to INSTALLED_APPS. Also add 'smart_selects' to urls.

path('chaining/', include('smart_selects.urls')),

Fassold