更新 Django Rest Framework 中的多对多关系

Question

Orders在我的 django 应用程序中，我在和之间建立了多对多关系Packages。一个订单可以有多个包裹。我想了解更新和创建方法模型.pyclass Package(models.Model):    prod_name = models.CharField(max_length=255, default=0)    quantity = models.IntegerField(default=0)    unit_price = models.IntegerField(default=0)class Orders(models.Model):    order_id = models.CharField(max_length=255, default=0)    package = models.ManyToManyField(Package)    is_cod = models.BooleanField(default=False)序列化程序.pyclass PackageSerializer(serializers.ModelSerializer):    class Meta:        model = Package        fields = "__all__"class OrderSerializer(serializers.ModelSerializer):    package = PackageSerializer(many=True)    class Meta:        model = Orders        fields = "__all__"视图.pyclass OrdersCreateAPIView(generics.CreateAPIView):    permission_classes = (permissions.IsAuthenticated,)    serializer_class = OrderSerializer    def post(self, request):        serializer = OrderSerializer(data=request.data)        if serializer.is_valid():            serializer.save()            return Response(serializer.data, status=status.HTTP_201_CREATED)        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)这足以处理相关数据吗？我正在尝试了解ManytoManyDjango 和 DRF 中的关系，所以请解释我是否需要更改模型或视图更新：我已经更新了我的序列化程序和视图，以便创建manytomany像这样的相关对象：class OrderSerializer(serializers.ModelSerializer):    package = PackageSerializer(many=True)    class Meta:        model = Orders        fields = "__all__"    def create(self, validated_data):        package_data = validated_data.pop('package')        pkgs = []        order = Orders.objects.create(**validated_data)        for i in package_data:            try:                p = Package.objects.create(**i)                pkgs.append(p)            except:                pass        order.package.set(pkgs)        return order但是我仍然不清楚覆盖update. RetrieveUpdateDestroyAPIView另外，上述方法是存储M2M相关对象的正确方法吗？请帮助更新序列化程序的部分，我知道我必须在序列化程序中传递查询

Answer 1

工作代码库

#serializers.py

class PackageSerializer(serializers.ModelSerializer):

    id = serializers.IntegerField()

    class Meta:

        model = Package

        fields = "__all__"

class OrderSerializer(serializers.ModelSerializer):

    package = PackageSerializer(many=True)

    def get_or_create_packages(self, packages):

        package_ids = []

        for package in packages:

            package_instance, created = Package.objects.get_or_create(pk=package.get('id'), defaults=package)

            package_ids.append(package_instance.pk)

        return package_ids

    def create_or_update_packages(self, packages):

        package_ids = []

        for package in packages:

            package_instance, created = Package.objects.update_or_create(pk=package.get('id'), defaults=package)

            package_ids.append(package_instance.pk)

        return package_ids

    def create(self, validated_data):

        package = validated_data.pop('package', [])

        order = Orders.objects.create(**validated_data)

        order.package.set(self.get_or_create_packages(package))

        return order

    def update(self, instance, validated_data):

        package = validated_data.pop('package', [])

        instance.package.set(self.create_or_update_packages(package))

        fields = ['order_id', 'is_cod']

        for field in fields:

            try:

                setattr(instance, field, validated_data[field])

            except KeyError:  # validated_data may not contain all fields during HTTP PATCH

                pass

        instance.save()

        return instance

    class Meta:

        model = Orders

        fields = "__all__"

#views.py

class OrderViewSet(viewsets.ModelViewSet):

    serializer_class = OrderSerializer

    queryset = Orders.objects.all()

DefaultRouter在as的帮助下注册此视图，

from rest_framework.routers import DefaultRouter

router = DefaultRouter()

router.register(r'order', OrderViewSet, basename='order')

urlpatterns = [

              ] + router.urls

因此，您将获得该表中描述的基本 CRUD 端点（参见DefaultRouter参考文献）。

让您的订单列表端点成为/foo-bar/order/

1. HTTP POST 来/foo-bar/order/创建一个新实例

2. HTTP PUT 或 HTTP PATCH/foo-bar/order/<ORDER_PK>/以更新内容

笔记

在这种情况下，id如果您希望将现有的包关系映射到Order

更新-1

您可以像这样连接视图

urlpatterns = [

    path('foo/order/', OrderViewSet.as_view({'post': 'create'})),  # create new Order instance

    path('foo/order/<int:pk>/', OrderViewSet.as_view({'patch': 'partial_update'})),  # update Order instance

]

注意：这仅支持HTTP POST和HTTP PATCH