小编Usm*_*ill的帖子

from django.db import models

class Pet(models.Model):
    SEX_CHOICES = [('M','Male'), ('F', 'Female')]
    name = CharField(max_length=100)
    submitter = CharField(max_length=100)
    species = CharField(max_length=30)
    breed = CharField(max_length=30, blank=True)
    description = models.TextField()
    sex = models.CharField(choices=SEX_CHOICES, max_length=1, blank=True)
    submission_date = models.DateTimeField()
    age = models.IntegerField(null=True)
    vaccinations = models.ManyToManyField('Vaccine', blank=True)


class Vaccine(models.Model):
    name = models.CharField(max_length=50)

使用此代码，我在运行“python manage.py makemigrations”时收到命令行错误。名称“CharField”未定义。

如何修复它。