Django级联保存？

Question

我的用户注册表上有一个方法，如下所示：

def save(self):
    user = User(
        username = self.cleaned_data['username'],
        email = self.cleaned_data['email1'],
        first_name = self.cleaned_data['first_name'],
        last_name = self.cleaned_data['last_name'],
    )
    user.set_password(self.cleaned_data['password1'])
    user.profile = Profile(
        primary_phone = self.cleaned_data['phone'],
    )
    user.profile.address = Address(
        country = self.cleaned_data['country'],
        province = self.cleaned_data['province'],
        city = self.cleaned_data['city'],
        postal_code = self.cleaned_data['postal_code'],
        street1 = self.cleaned_data['street1'],
        street2 = self.cleaned_data['street2'],
        street3 = self.cleaned_data['street3'],
    )
    user.save()
    return user

问题是当我调用form.save() 时，它会按预期创建user 对象，但不会保存他的个人资料或地址。为什么不级联保存所有子模型？我怀疑我可以手动调用user.profile.save() 和user.profile.address.save()，但我希望整个事情一起成功或失败。最好的方法是什么？

---

目前的解决方案：

def save(self):
    address = Address(
        country = self.cleaned_data['country'],
        province = self.cleaned_data['province'],
        city = self.cleaned_data['city'],
        postal_code = self.cleaned_data['postal_code'],
        street1 = self.cleaned_data['street1'],
        street2 = self.cleaned_data['street2'],
        street3 = self.cleaned_data['street3'],
    )
    address.save()

    user = User(
        username = self.cleaned_data['username'],
        email = self.cleaned_data['email1'],
        first_name = self.cleaned_data['first_name'],
        last_name = self.cleaned_data['last_name'],
    )
    user.set_password(self.cleaned_data['password1'])
    user.save()

    profile = Profile(
        primary_phone = self.cleaned_data['phone'],
    )
    profile.address = address
    profile.user = user
    profile.save()

我必须将profile 设为“中心”对象。需要设置 profile.user = user 而不是 user.profile = profile 才能使其工作（我猜是因为密钥在配置文件模型上，而不是在用户模型上）。

---

较新的解决方案：

我从this article 中得到了提示，在this answer 中建议。

现在我已经分离了我的模型表单并将逻辑移到了视图中：

def register(request):
    if request.POST:
        account_type_form = forms.AccountTypeForm(request.POST)
        user_form = forms.UserForm(request.POST)
        profile_form = forms.ProfileForm(request.POST)
        address_form = forms.AddressForm(request.POST)

        if user_form.is_valid() and profile_form.is_valid() and address_form.is_valid():
            user = user_form.save()
            address = address_form.save()
            profile = profile_form.save(commit=False)
            profile.user = user
            profile.address = address
            profile.save()
            return HttpResponseRedirect('/thanks/')
    else:
        account_type_form = forms.AccountTypeForm()
        user_form = forms.UserForm()
        profile_form = forms.ProfileForm()
        address_form = forms.AddressForm()

    return render_to_response(
        'register.html',
        {'account_type_form': account_type_form, 'user_form': user_form, 'address_form': address_form, 'profile_form': profile_form},
        context_instance=RequestContext(request)
    )

我不太喜欢将负担转移到视图上，但我想这样我会获得更多的灵活性？

Answer 1

问题是您正在尝试创建或更新用户对象中甚至还不存在的字段。所以其他字段并没有真正更新，因为它们没有与子字段的任何主键相关联。

每次实例化新的模型字段时，都必须确保正在保存，以便子模型字段具有要关联的 id（主键）。

你需要更多这样的东西：

def save(self):
    user = User(
        username = self.cleaned_data['username'],
        email = self.cleaned_data['email1'],
        first_name = self.cleaned_data['first_name'],
        last_name = self.cleaned_data['last_name'],
    )
    ## save user so we get an id
    user.save()

    ## make sure we have a user.id
    if user.id:
        ## this doesn't save the password, just updates the working instance
        user.set_password(self.cleaned_data['password1'])
        user.profile = Profile(
            primary_phone = self.cleaned_data['phone'],
        )
        ## save the profile so we get an id
        user.profile.save()

    ## make sure we have a profile.id
    if user.profile.id:
        user.profile.address = Address(
            country = self.cleaned_data['country'],
            province = self.cleaned_data['province'],
            city = self.cleaned_data['city'],
            postal_code = self.cleaned_data['postal_code'],
            street1 = self.cleaned_data['street1'],
            street2 = self.cleaned_data['street2'],
            street3 = self.cleaned_data['street3'],
        )
        ## save the profile address
        user.profile.address.save()

    ## final save to commit password and profile changes
    user.save()
    return user

你在这里进行的这种级联save() 的事情感觉不对。那里很容易出现太多错误，如果任何字段不能保存，您最终会得到一个部分完整的用户实例，并且如果用户必须返回并重试，则可能会导致重复。不好玩！

编辑：删除了第二部分，因为它不准确。

Answer 2

它不会级联保存，因为它实际上并不知道是否需要保存其他对象。

一气呵成，先start a transaction：

@transaction.commit_on_success
def save(self):
  ....

然后按顺序保存子对象：

  user.profile.address.save()
  user.profile.save()
  user.save()