如何在django中选择从另一个模型中键入外键的所有对象？

Question

Sorry for title, I do not know how else to express myself.

For example, I have this three models:

class Person(models.Model):
    name = models.CharField()

class Teacher(models.Model):
    person = models.ForeignKey(Person)
    subject = models.CharField()

class Student(models.Model):
    person = models.ForeignKey(Person)
    grade = models.CharField()

How can I select all Person models that are Teachers ?

Answer 1

Person.objects.filter(teacher__isnull=False) 
# return Person who has a teacher pointing to it