小编Ade*_*ina的帖子

我正在尝试运行我的代码，但收到此错误：

  File "C:\Users\JOSHUA\Documents\ypgforum\myproject\boards\models.py", line 13, in <module>
    class Topic(models.Model):
  File "C:\Users\JOSHUA\Documents\ypgforum\myproject\boards\models.py", line 16, in Topic
    board = models.ForeignKey(Board, related_name='topics')
TypeError: __init__() missing 1 required positional argument: 'on_delete'

这是它指向的 models.py：

class Topic(models.Model):
    subject = models.CharField(max_length=255)
    last_updated = models.DateTimeField(auto_now_add=True)
    board = models.ForeignKey(Board, related_name='topics')
    starter = models.ForeignKey(User, related_name='topics')
    last_updated = models.DateTimeField(auto_now_add=True)