models.py

from django.db import models


class Country(models.Model):
    isocode = models.IntegerField(primary_key=True)
    iso = models.CharField(max_length=2)
    iso3 = models.CharField(max_length=3)
    fips = models.TextField(null=True)
    name = models.TextField(null=True)
    capital = models.TextField(null=True)
    geonameid = models.BigIntegerField(null=True)


class Region(models.Model):
    isocode = models.ForeignKey(Country, db_column="isocode", on_delete=models.PROTECT)
    regcode = models.TextField()
    name = models.TextField(null=True)
    geonameid = models.BigIntegerField(primary_key=True)

    class Meta:
        constraints = [
            models.UniqueConstraint(
                fields=["isocode", "regcode"], name="unique_country_and_region"
            )
        ]


class District(models.Model):
    name = models.TextField(null=True)
    geonameid = models.BigIntegerField(primary_key=True)

    isocode = models.ForeignKey(Country, db_column="isocode", on_delete=models.PROTECT)
    regcode = models.TextField()
    discode = models.TextField()

    class Meta:
        constraints = [
            models.UniqueConstraint(
                fields=["isocode", "regcode", "discode"],
                name="unique_district_and_region",
            )
        ]


class GeoName(models.Model):
    geonameid = models.BigIntegerField(primary_key=True)
    name = models.TextField(null=True)
    latitude = models.FloatField(null=True)
    longitude = models.FloatField(null=True)

    isocode = models.ForeignKey(
        Country, null=True, db_column="isocode", on_delete=models.PROTECT
    )
    regcode = models.TextField(null=True)
    discode = models.TextField(null=True)

    population = models.BigIntegerField(null=True)
    elevation = models.BigIntegerField(null=True)

    def __repr__(self):
        class_name = type(self).__name__
        return f"{class_name}<name={self.name!r}, regcode={self.regcode!r}>"