""" One-to-one relationships To define a one-to-one relationship, use ``OneToOneField()``. In this example, a ``Place`` optionally can be a ``Restaurant``. """ from django.db import models class Place(models.Model): name = models.CharField(max_length=50) address = models.CharField(max_length=80) def __str__(self): return "%s the place" % self.name class Restaurant(models.Model): place = models.OneToOneField(Place, models.CASCADE, primary_key=True) serves_hot_dogs = models.BooleanField(default=False) serves_pizza = models.BooleanField(default=False) def __str__(self): return "%s the restaurant" % self.place.name class Bar(models.Model): place = models.OneToOneField(Place, models.CASCADE) serves_cocktails = models.BooleanField(default=True) class UndergroundBar(models.Model): place = models.OneToOneField(Place, models.SET_NULL, null=True) serves_cocktails = models.BooleanField(default=True) class Waiter(models.Model): restaurant = models.ForeignKey(Restaurant, models.CASCADE) name = models.CharField(max_length=50) def __str__(self): return "%s the waiter at %s" % (self.name, self.restaurant) class Favorites(models.Model): name = models.CharField(max_length=50) restaurants = models.ManyToManyField(Restaurant) class ManualPrimaryKey(models.Model): primary_key = models.CharField(max_length=10, primary_key=True) name = models.CharField(max_length=50) class RelatedModel(models.Model): link = models.OneToOneField(ManualPrimaryKey, models.CASCADE) name = models.CharField(max_length=50) class MultiModel(models.Model): link1 = models.OneToOneField(Place, models.CASCADE) link2 = models.OneToOneField(ManualPrimaryKey, models.CASCADE) name = models.CharField(max_length=50) def __str__(self): return "Multimodel %s" % self.name class Target(models.Model): name = models.CharField(max_length=50, unique=True) class Pointer(models.Model): other = models.OneToOneField(Target, models.CASCADE, primary_key=True) class Pointer2(models.Model): other = models.OneToOneField(Target, models.CASCADE, related_name="second_pointer") class HiddenPointer(models.Model): target = models.OneToOneField(Target, models.CASCADE, related_name="hidden+") class ToFieldPointer(models.Model): target = models.OneToOneField( Target, models.CASCADE, to_field="name", primary_key=True ) # Test related objects visibility. class SchoolManager(models.Manager): def get_queryset(self): return super().get_queryset().filter(is_public=True) class School(models.Model): is_public = models.BooleanField(default=False) objects = SchoolManager() class DirectorManager(models.Manager): def get_queryset(self): return super().get_queryset().filter(is_temp=False) class Director(models.Model): is_temp = models.BooleanField(default=False) school = models.OneToOneField(School, models.CASCADE) objects = DirectorManager()