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import datetime
from django.db import models
class Country(models.Model):
# Table Column Fields
name = models.CharField(max_length=50)
def __str__(self):
return self.name
class Person(models.Model):
# Table Column Fields
name = models.CharField(max_length=128)
person_country_id = models.IntegerField()
# Relation Fields
person_country = models.ForeignObject(
Country,
from_fields=["person_country_id"],
to_fields=["id"],
on_delete=models.CASCADE,
)
friends = models.ManyToManyField("self", through="Friendship", symmetrical=False)
class Meta:
ordering = ("name",)
def __str__(self):
return self.name
class Group(models.Model):
# Table Column Fields
name = models.CharField(max_length=128)
group_country = models.ForeignKey(Country, models.CASCADE)
members = models.ManyToManyField(
Person, related_name="groups", through="Membership"
)
class Meta:
ordering = ("name",)
def __str__(self):
return self.name
class Membership(models.Model):
# Table Column Fields
membership_country = models.ForeignKey(Country, models.CASCADE, null=True)
date_joined = models.DateTimeField(default=datetime.datetime.now)
invite_reason = models.CharField(max_length=64, null=True)
person_id = models.IntegerField()
group_id = models.IntegerField(blank=True, null=True)
# Relation Fields
person = models.ForeignObject(
Person,
from_fields=["person_id", "membership_country"],
to_fields=["id", "person_country_id"],
on_delete=models.CASCADE,
)
group = models.ForeignObject(
Group,
from_fields=["group_id", "membership_country"],
to_fields=["id", "group_country"],
on_delete=models.CASCADE,
)
class Meta:
ordering = ("date_joined", "invite_reason")
def __str__(self):
group_name = self.group.name if self.group_id else "NULL"
return "%s is a member of %s" % (self.person.name, group_name)
class Friendship(models.Model):
# Table Column Fields
from_friend_country = models.ForeignKey(
Country, models.CASCADE, related_name="from_friend_country"
)
from_friend_id = models.IntegerField()
to_friend_country_id = models.IntegerField()
to_friend_id = models.IntegerField(null=True)
# Relation Fields
from_friend = models.ForeignObject(
Person,
on_delete=models.CASCADE,
from_fields=["from_friend_country", "from_friend_id"],
to_fields=["person_country_id", "id"],
related_name="from_friend",
)
to_friend_country = models.ForeignObject(
Country,
from_fields=["to_friend_country_id"],
to_fields=["id"],
related_name="to_friend_country",
on_delete=models.CASCADE,
)
to_friend = models.ForeignObject(
Person,
from_fields=["to_friend_country_id", "to_friend_id"],
to_fields=["person_country_id", "id"],
related_name="to_friend+",
on_delete=models.CASCADE,
)
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