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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)
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()
# 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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