Django，查询集返回许多 self

Question

遵循常规的多对多查询集逻辑会给我错误。我想因为它与 self 有关，我可能需要做一些额外的魔法，但我不知道是什么魔法。

型号:

class Entry(models.Model):
    title   =   models.CharField(max_length=100, verbose_name='title')
    related     =   models.ManyToManyField('self', related_name='related_entries', blank=True)

查询集:

entry = Entry.objects.get(pk=1)
related = entry.related_entries.all()

错误:'Entry' 对象没有属性 'related_entries'

Answer 1

查看 symmetrical 的文档ManyToManyField 的参数:

When Django processes this model, it identifies that it has a ManyToManyField on itself, and as a result, it doesn't add a person_set attribute to the Person class. Instead, the ManyToManyField is assumed to be symmetrical -- that is, if I am your friend, then you are my friend.

If you do not want symmetry in many-to-many relationships with self, set symmetrical to False. This will force Django to add the descriptor for the reverse relationship, allowing ManyToManyField relationships to be non-symmetrical.

所以，为了使用 related_name，设置 symmetrical=False。