Question

我无法为我认为是初学者的问题找到合适的解决方案。我们非常感谢您的帮助。

我正在建立的网站将用于计划聚会。有两种类型的人可以使用它：聚会组织者和聚会访客。派对组织者可以创建一个派对并选择要提供给访问者的项目。项目是食物和饮料，一项=一份比萨饼或一份啤酒。

然后，用户将能够确认该聚会的参与，并选择他们想要订购的食物和饮料以及数量。我已经创建了身份验证和创建了聚会。

现在，我的问题是这样：

组织者如何创建要提供给访客？
访客如何选择两者类型的物品和数量？

我尝试使用以下代码（已整理）：

models.py：

class ItemType(models.Model):
    """Create items (food and drinks)."""
    name = models.CharField()

class Party(models.Model):
    """Create a party."""
    organizer = models.ForeignKey(User)
    party_name = models.CharField()
    items_to_be_offered = models.ManyToManyField(ItemType)

class PartyRegistration(models.Model):
    """Register for a party / create party registration."""
    party = models.ForeignKey(Party)
    visitor = models.CharField()
    selected_items = models.ManyToManyField()

class ItemSelection(models.Model):
    """Specify which items and number of items the visitor selected."""
    party_registration = models.OneToOneField(PartyRegistration)
    item_type = models.ManyToManyField(ItemType)
    item_quantity = models.PositiveIntegerField()

forms.py

class VisitorRegisterForm(forms.ModelForm):
    """Form to register a visitor."""

    class Meta:
        model = PartyRegistration
        fields = ['visitor', 'selected_items']

views.py

def VisitorRegister(request, pk):
    """Register Visitor to a specific party."""    
    party = get_object_or_404(Party, pk=pk)    

    if request.method == 'POST':
        form = VisitorRegisterForm(request.POST)
        if form.is_valid():
            name_clean = form.cleaned_data['visitor']
            registration = PartyRegistration(party=party, visitor=name_clean)
            registration.save()
            return HttpResponseRedirect(reverse('index'))
    else:
        form = VisitorRegisterForm()

    context = {'form': form, 'party': party}

    return render(request, 'visitor-register.html', context)

网站是Django 2.0，PostgreSQL。

Answer 1

在这种情况下，您需要使用through模型与ManyToMany关系（顺序很重要，或更改顺序并引用PartyRegistration）：

class PartyRegistration(models.Model):
    """Register for a party / create party registration."""
    party = models.ForeignKey(Party)
    visitor = models.CharField()
    selected_items = models.ManyToManyField(ItemType, through='ItemSelection')

class ItemSelection(models.Model):
    """Specify which items and number of items the visitor selected."""
    party_registration = models.ForeignKey(PartyRegistration)
    item_type = models.ForeignKey(ItemType)
    item_quantity = models.PositiveIntegerField(default=1)

    class Meta:
        unique_together = ('party_registration', 'item_type')

请参见https://docs.djangoproject.com/en/2.1/topics/db/models/#intermediary-manytomany

Django-从预先创建的列表中选择项目和数量

1 个答案: