python - 'NoneType' 对象没有属性 'nazev_zanru' 虽然它应该有

Question

美好的一天社区，我需要你的帮助，因为我无法继续我的项目。Django model.py 返回一个AttributeError: 'NoneType' object has no attribute 'nazev_zanru'

我的models.py如下；

from django.db import models


class Zanr(models.Model):
    nazev_zanru = models.CharField(max_length=80, verbose_name="Žánr")

    def __str__(self):
        return "Nazev_zanru: {0}".format(self.nazev_zanru)

    class Meta:
        verbose_name = "Žánr"
        verbose_name_plural = "Žánry"


class Film(models.Model):
    nazev = models.CharField(max_length=200, verbose_name="Název Filmu")
    rezie = models.CharField(max_length=180, verbose_name="Režie")
    zanr = models.ForeignKey(Zanr, on_delete=models.SET_NULL, null=True, verbose_name="Žánr")

    def __str__(self):
        return "Nazev: {0} | Rezie: {1} | Zanr: {2}".format(self.nazev, self.rezie, self.zanr.nazev_zanru)

    class Meta:
        verbose_name = "Film"
        verbose_name_plural = "Filmy"

据我了解，

def __str__(self):
    return "Nazev: {0} | Rezie: {1} | Zanr: {2}".format(self.nazev, self.rezie, self.zanr.nazev_zanru)

代码是指 zanr = models.ForeignKey(Zanr, on_delete=models.SET_NULL, null=True, verbose_name="Žánr") 通过

class Zanr(models.Model):
    nazev_zanru = models.CharField(max_length=80, verbose_name="Žánr")

    def __str__(self):
        return "Nazev_zanru: {0}".format(self.nazev_zanru)

` 因此定义。错误在哪里？迁移、URL 和管理完成。

提前谢谢你，大卫

标签： pythondjangodjango-modelsattributeerror