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我正在尝试以特定格式获取数据，但无法获得所需的输出。

我的模型：

class Category(models.Model):
    name = models.CharField(max_length=40)


class Expense(models.Model):

    category = models.ForeignKey(Category, on_delete=models.CASCADE, related_name="category_name")
    description = models.CharField(max_length=200)
    total_amount = models.IntegerField()


class Expense_Details(models.Model):

    expense = models.ForeignKey(Expense, on_delete=models.CASCADE, related_name="payment")  
    user = models.IntegerField()
    amount = models.FloatField()
    type = models.CharField(max_length=100)   ---->type is owe or lend

当我要求/api/expenses/：

Expected Output
{
  “total_expenses”: 10, 
  “Expenses”: 
               [{
               “id”: 1,
               “category”: 1,
               “created_by”: 1,     ------> user logged id
               “description”: “lunch”,
               “total_amount”: “105”,
               “owe”: [{
                        “user_id”: 1,
                        “amount”: 10
                      },
                      {
                        “user_id”: 2,
                        “amount”: 95
                       }],

               “lend”: [{
                        “user_id”: 3,
                        “amount”: 10
                      },
                      {
                        “user_id”: 4,
                        “amount”: 95
                       }],
                  }, ...
                  ]
  }

我的输出：

  {
"results": [
    {
        "id": 1,
        "category": 1,
        "description": "lunch at the burj al arab",
        "total_amount": 105,
        "payment": [
            {
                "user": 1,
                "amount": -10
            },
            {
                "user": 2,
                "amount": -95
            },
            {
                "user": 3,
                "amount": 10
            },
            {
                "user": 4,
                "amount": 95
            }
        ]
      }
    ]
 }

我的序列化器：

class ExpenseDetailsSerializer(serializers.ModelSerializer):
    class Meta:
        model = Expense_Details
        fields = ['user', 'amount']


class ExpenseSerializer(serializers.ModelSerializer):
    payment = serializers.SerializerMethodField()

    def get_payment(self, obj):
        return ExpenseDetailsSerializer(obj.payment.all(), many=True).data

    class Meta:
        model = Expense
        fields = ['id', 'category', 'description', 'total_amount', 'payment',]

我应该使用什么查询来获取上述格式的输出？我的序列化器会是什么样子？我怎样才能分开ownand lend？我还存储了自己的并借用+并-签名以区分它们。

4

1 回答 1

0

使用 aListField相同。

文档：https ://www.django-rest-framework.org/api-guide/fields/#listfield

另请参阅如何在 Django REST 框架中序列化“对象列表”

在这里您可以尝试以下操作：

class ExpenseSerializer(serializers.Serializer):
    payment = serializers.ListField(child=ExpenseDetailsSerializer())

    def get_payment(self, obj):
        return ExpenseDetailsSerializer(obj.payment.all(), many=True).data

    class Meta:
        model = Expense
        fields = ['id', 'category', 'description', 'total_amount', 'payment',]
于 2020-05-21T09:25:02.500 回答