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)

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? — doniyor, Oct 01 '16 at 13:04
@doniyor - 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 — Far, Oct 01 '16 at 13:26

score 3 · Accepted Answer · answered Oct 01 '16 at 14:08

3

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.

answered Oct 01 '16 at 14:08

ger.s.brett

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@far did you succeed ?? – kahuria00 Sep 15 '21 at 14:32

score 1 · Answer 2 · answered Apr 27 '21 at 19:07

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')),

score 0 · Answer 3 · answered Oct 01 '16 at 13:37

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)

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

3 Answers3