Django婚恋网站模型__str__返回NoneType且点击编辑自动删数据

问题现象 #

我在开发基础婚恋网站，支持用户上传个人资料，资料需经管理员审核后公开展示。最初资料增删改查功能正常，尝试添加userForeignKey模块实现用户自动关联功能后出现两个问题：

• 报错 __str__ returned non-string (type NoneType)
• 点击编辑profile，还没打开表单页，对应profile的全部数据就会从数据库删除，所有字段显示为null，操作发生在加载带实例的表单之前

卸载模块、回退到之前正常版本后问题仍未解决。同样的更新逻辑用在其他模型上无报错，仅该模型存在问题。

相关代码 #

模型代码 #

class matrimony_db(models.Model):
    category = (
        ('MALE', 'Male'),
        ('FEMALE', 'Female'),
    )
    challenge =  (
        ('Yes', 'Yes'),
        ('No', 'No'),
    )
    ms =  (
        ('Single', 'Single'),
        ('Married', 'Married'),
        ('Divorced', 'Divorced'),
        ('widow', 'widow'),
        ('widower', 'widower'),
    )
    # 个人信息
    img = models.ImageField(upload_to = 'matrimony/')
    name = models.CharField(max_length=100,null = True, blank = True)
    dob = models.DateField(null = True, blank = True)
    gender = models.CharField(max_length = 10, choices = category,null = True, blank = True)
    phone = models.CharField(max_length=50,null = True, blank = True)
    bio = models.TextField(null = True, blank = True)
    # 职业与教育信息
    occupation = models.CharField(max_length = 200,null = True, blank = True)
    Highest_Education =  models.CharField(max_length = 500,null = True, blank = True)
    # 身体信息
    Height = models.CharField(max_length = 200,null = True, blank = True)
    weight = models.CharField(max_length = 200,null = True, blank = True)
    physical_challenge=models.CharField(max_length = 10, choices = challenge,null = True, blank = True)
    Physical_remarks =  models.CharField(max_length = 500,null = True, blank = True)
    # 婚姻与居住地信息
    Marital_status = models.CharField(max_length=50, choices = ms,null = True, blank = True)
    Languages = models.CharField(max_length = 200,null = True, blank = True)
    currentplace = models.CharField(max_length = 200,null = True, blank = True)
    # 家庭信息
    father = models.CharField(max_length=200,null = True, blank = True)
    mother = models.CharField(max_length=200,null = True, blank = True)
    mother_occupation = models.CharField(max_length=200,null = True, blank = True)
    father_occupation = models.CharField(max_length=200,null = True, blank = True)
    siblings = models.TextField(null = True, blank = True)
    # 择偶要求
    spouse = models.TextField(null = True, blank = True)

    def __str__(self):
        return self.name

    def delete(self, *args, **kwargs):
        self.img.delete()
        super().delete(*args, **kwargs)

表单代码 #

class form_matrimony(forms.ModelForm):
    img = forms.ImageField(required=False)
    class Meta:
        model = matrimony_db
        fields = '__all__'

视图代码 #

def view_update_matrimony(request, pk):
    book = matrimony_db.objects.get(pk=pk)
    form = form_matrimony(instance=book)
    if request.method == 'POST':
        forms = form_matrimony(request.POST,request.FILES,instance = book )
        if forms.is_valid():
            forms.save()
            sb = str(book)
            messages.success(request, 'Files in ' +sb + " updated successfully")
            return redirect('admin_matrimony')
    else:
        form = form_matrimony()
    return render(request,'admin_loc_matrimony_new.html',{'form':form})

注意：尝试部分修复方法后，类型错误不再出现，但数据仍会被自动删除。

内容的提问来源于stack exchange，提问作者Ben