Django model.foreignKey并返回self.text错误 [英] Django model.foreignKey and return self.text errors

问题描述

因此，我正在Django中处理model.py，并且出现2个pylint错误.我不明白为什么?这是pylint的问题还是我的代码做错了?

So I'm working on the model.py in Django and i'm getting 2 pylint errors. I don't understand why? is this an issue with pylint or something i'm doing wrong in my code.

E1120:No value for argument 'on_delete' in constructor call    
E1136:Value 'self.text' is unsubscriptable

• 第一个在Entry的第19行topic = models.ForeignKey(Topic)

  • The first is on line 19, in Entry topic = models.ForeignKey(Topic)

    第二个是第24行self.text [:50]

    The second is on line 24 self.text[:50]

    如果我删除条目类，则代码有效

    If I remove the entry class the code works

    from django.db import models
    
    # Create your models here.
    class Topic(models.Model):
    """A topic the user is learning about"""
    text = models.CharField(max_length=200)
    date_added = models.DateTimeField(auto_now_add=True)
    
    def __str__(self):
        """Return a string representation of the model."""
        return self.text
    
    class Entry(models.Model):
    """Something specific learned about a topic"""
    topic = models.ForeignKey(Topic)
    text = models.TextField()
    date_added = models.DateTimeField(auto_now_add=True)
    
    class Meta:
        verbose_name_plural = "entries"
    
    def __str__(self):
        """Return a string representation of the model."""
        return self.text[:50] + "..."
    

    推荐答案

    问题是Django 1.9中的ForeignKey需要Django 2.0中的1个位置参数.

    The problem was ForeignKey in Django 1.9 required 1 positional argument in Django 2.0 ForeignKey 2 required positional argument

      topic = models.ForeignKey("Topic", on_delete=models.PROTECT)
    

    这篇关于Django model.foreignKey并返回self.text错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！