如何修复django.db.utils.IntegrityError：NOT NULL约束失败：new__exp_answer.user_id

Question

我正在尝试修复django.db.utils.IntegrityError：NOT NULL约束失败：new__exp_answer.user_id

from django.db import models
from django.contrib.auth.models import User

class Question(models.Model):
     userquestion=models.CharField(max_length=30,null=True,blank=True)
     def __str__(self):
    return self.userquestion
@property
def question(self):
    return self.answer_set.all()
@property
def votes(self):
    return self.answer_set.count()

class Answer（models.Model）

key=models.ForeignKey('Question', on_delete=models.CASCADE,null=True)

kess=models.ManyToManyField('Question', related_name= 'userquestion1')

useranswer=models.CharField(max_length=30,null=True,blank=True)

image1=ImageField(upload_to='media/images',default="",null=True,blank=True)

def __str__(self):
    return self.useranswer

class Relate（models.Model）：

users=models.ForeignKey(User,on_delete=models.CASCADE,null=True)

kess1=models.ManyToManyField('Answer', related_name= '  userquestion12 ')

def __str__(self):
    return self.users.first_name