django，related_name，外键

Question

我必须在Django中执行以下代码：

class User(models.Model):
    username = models.CharField(max_length=50, unique=True)
    password = models.CharField(max_length=15)

class Follows(models.Model):
    user = models.ManyToManyField(User, related_name = 'Isread+')
    follower = models.ManyToManyField(User, related_name = 'Reads+')

当我尝试执行此操作时，出现错误：

>>> from twitter.models import *
>>> u1 = User.objects.all()[0]
>>> u2 = User.objects.all()[1]
>>> Follows.objects.create(user = u1, follower = u2)
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "C:\Python33\lib\site-packages\django\db\models\manager.py", line 149, in create
    return self.get_query_set().create(**kwargs)
  File "C:\Python33\lib\site-packages\django\db\models\query.py", line 414, in create
    obj = self.model(**kwargs)
  File "C:\Python33\lib\site-packages\django\db\models\base.py", line 415, in __init__
    raise TypeError("'%s' is an invalid keyword argument for this function" % list(kwargs)[0])
TypeError: 'follower' is an invalid keyword argument for this function

有谁知道为什么会这样？ 提前谢谢。

Answer 1

当您具有ManyToManyField时，首先需要创建Follows对象（保存它），以便它具有主键才能使多对多关系起作用。 另外，您需要使用ManyToManyManager将项目添加到关系中。

简而言之，您需要执行以下操作：

f = Followers()
f.save()
f.user.add(u1)
f.follower.add(u2)
f.save()