将数据从 ChoiceField 保存到数据库 Django

Question

我是 Django 的新手，我构建了一个显示单个 select 字段供选择的表单。字段中的数据由表单实时计算。

我现在需要在提交数据后保存在数据库中。唯一的问题是，出于某种原因，我得到了 IntegrityError error NOT NULL constraint failed: manager_playlist.user_id

下面是我在 Django 中的视图、表单和模型

views.py

def playlist(request):
    if not is_user_already_auth_spotify(request):
        messages.error(request, "You're not authenticated with Spotify, please authenticate here")
        return redirect('/members/account/' + request.user.username)

    if request.method == "POST":
        form = ChoosePlaylistForm(request.POST, request=request)
        if form.is_valid():
            form.save()
            messages.success(request, "Playlist successfully chosen")
            return HttpResponseRedirect('account')
        else:
            pass
    else:
        form = ChoosePlaylistForm(request=request)

    return render(request, 'show_playlist.html', {"playlist_choose_form": form})

forms.py

class ChoosePlaylistForm(ModelForm):

    playlists = forms.ChoiceField(choices=())

    class Meta:
        model = Playlist
        fields = ('playlists',)

    def __init__(self, *args, request=None, **kwargs):
        super(ChoosePlaylistForm, self).__init__(*args, **kwargs)
        self.request = request
        self.fields['playlists'].choices = self.generate_selection()

    def generate_selection(self):
        sp_auth, cache_handler = spotify_oauth2(self.request)
        spotify = spotipy.Spotify(oauth_manager=sp_auth)
        s_user = spotify.current_user()
        u_playlists = spotify.user_playlists(s_user['id'], limit=10)

        choices = []
        for playlist in u_playlists["items"]:
            if playlist["owner"]["id"] == s_user['id']:
                playlist_choice = (playlist["id"], playlist["name"])
                choices.append(playlist_choice)
            else:
                pass

        return choices

model.py

class Playlist(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE)
    playlists = models.CharField(max_length=50, null=True, blank=True)  # playlists are the ids of the playlists

    def __str__(self):
        return self.playlists

Answer 1

错误原因是新建Playlist对象时，user字段不能为空（你没有加null=True，当然加了也没意义）。现在表单通过验证，因为表单不需要用户字段，只需要播放列表字段。你有几个选择。

选项 1
将必填字段添加到您的表单（我还没有测试过，请检查 docs！）：

class ChoosePlaylistForm(ModelForm):

    playlists = forms.ChoiceField(choices=())

    class Meta:
        model = Playlist
        fields = ('playlists', 'user',)   # NOTE THE CHANGE HERE

    def __init__(self, *args, request=None, **kwargs):
        super(ChoosePlaylistForm, self).__init__(*args, **kwargs)
        self.request = request
        self.user = request.user    # Add the user to the form

选项 2
使用 commit=False 按原样保存表单，然后在保存模型之前添加缺少的字段：

if request.method == "POST":
        form = ChoosePlaylistForm(request.POST, request=request)
        if form.is_valid():
            playlist = form.save(commit=False)    # NOTE THE CHANGE HERE
            playlist.user = request.user          # Add the user to the partial playlist
            playlist.save()                       # Now you can save the playlist
            
            messages.success(request, "Playlist successfully chosen")
            return HttpResponseRedirect('account')

选项 3
在实例化表单本身时添加字段（我不确定我的语法是否正确）：

form = ChoosePlaylistForm(request.POST, request=request, instance=request.user)

编辑
上面的选项 3 似乎不起作用。我相信此编辑将：

form = ChoosePlaylistForm(request.POST, request=request, initial={'user': request.user})

将数据从 ChoiceField 保存到数据库 Django

Save data from ChoiceField to database Django

python

django

django-models

django-forms

views.py

forms.py

model.py