如何在移植模型时修复移植错误

Question

在CLI中使用命令时，用于迁移在Django中创建的模型

python manage.py migrate

CLI显示错误

__init__() missing 1 required positional argument: 'on_delete'

代码如下：

from django.db import models

class Topic(models.Model):

    top_name = models.CharField(max_length=264,unique=True)

    def __str__(self):
        return self.top_name

class Webpage(models.Model):

    topic = models.ForeignKey(Topic)
    name = models.CharField(max_length=264,unique=True)
    url = models.URLField(unique=True)

    def __str__(self):
        return self.name

class AccessRecord(models.Model):

    name = models.ForeignKey(Webpage)
    date = models.DateField()

    def __str__(self):
        return str(self.date) 

Answer 1

因为该行中缺少1个必需的位置参数：'on_delete‘。

topic = models.ForeignKey(Topic,on_delete=models.CASCADE)
name = models.ForeignKey(Webpage,on_delete=models.CASCADE)

Django

“多对一关系。需要两个位置参数:与模型相关的类和on_delete选项。”

For further details Django Documentation