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from django.db import models
from django.db.models.functions import UUID4
class School(models.Model):
name = models.CharField(max_length=100)
class Parent(models.Model):
name = models.CharField(max_length=100)
class Child(models.Model):
mother = models.ForeignKey(Parent, models.CASCADE, related_name="mothers_children")
father = models.ForeignKey(Parent, models.CASCADE, related_name="fathers_children")
school = models.ForeignKey(School, models.CASCADE)
name = models.CharField(max_length=100)
class Meta:
constraints = [
models.UniqueConstraint("mother", "father", name="unique_parents"),
]
class ParentUUIDPk(models.Model):
uuid = models.UUIDField(primary_key=True, db_default=UUID4(), editable=False)
class Meta:
required_db_features = {
"supports_uuid4_function",
"supports_expression_defaults",
}
class ChildUUIDPk(models.Model):
parent = models.ForeignKey(ParentUUIDPk, models.CASCADE)
name = models.CharField(max_length=100)
class Meta:
required_db_features = {
"supports_uuid4_function",
"supports_expression_defaults",
}
class Poet(models.Model):
name = models.CharField(max_length=100)
def __str__(self):
return self.name
class Poem(models.Model):
poet = models.ForeignKey(Poet, models.CASCADE)
name = models.CharField(max_length=100)
class Meta:
unique_together = ("poet", "name")
def __str__(self):
return self.name
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