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from django.db import models
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class Person(models.Model):
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name = models.CharField(max_length=200)
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class Movie(models.Model):
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title = models.CharField(max_length=200)
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director = models.ForeignKey(Person)
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class Event(models.Model):
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class Screening(Event):
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movie = models.ForeignKey(Movie)
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class ScreeningNullFK(Event):
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movie = models.ForeignKey(Movie, null=True)
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class Package(models.Model):
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screening = models.ForeignKey(Screening, null=True)
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class PackageNullFK(models.Model):
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screening = models.ForeignKey(ScreeningNullFK, null=True)