验证Django queryset相关对象参数的类型

Question

Does django provide a way to validate the model type in django queryset when for example filtering by related objects? Let's say we have the following models:

class Person(models.Model):
    name = models.CharField(max_length=5)

class Author(models.Model):
    name = models.CharField(max_length=25)

class Book(models.Model):
    name = models.CharField(max_length=5)
    author = models.ForeignKey(Author)

And

p = Person.objects.all().first()
query = Book.objects.filter(author=p)

filters all books which auhtor_id is equal to given person_id (p_id), although Book refers to Author, not to Person.

Of course this is the responsibility of a programmer to avoid such errors but it's sitll possible.

This happens in django 1.7

Answer 1

p = Person.objects.all().first()
query = Book.objects.filter(author=p)

Did you actually try this? According to me it should raise a ValueError Something along the lines of 'Must be a Author instance"

Now if you want to avoid this error, you need to use an id, and Moses as usual has a good answer showing how it's done.

Answer 2

如果author_id与author_id相同， person_id可以直接使用id进行过滤 ：

query = Book.objects.filter(author_id=p.id)