Django数据入库报错：Basetable接收到意外关键字参数

报错信息 #

TypeError: Basetable() got unexpected keyword arguments: 'CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents'

需求数据 #

需存入数据库的JSON结构：

jsonToUse = {
    "CompanyId": "320193",
    "CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents": [
        {
            "decimals": "-6",
            "unitRef": "usd",
            "value": "39789000000"
        },
        {
            "decimals": "-6",
            "unitRef": "usd",
            "value": "50224000000"
        },
        {
            "decimals": "-6",
            "unitRef": "usd",
            "value": "25913000000"
        },
        {
            "decimals": "-6",
            "unitRef": "usd",
            "value": "35929000000"
        }
    ]
}

当前Model定义 #

class Basetable(models.Model):
    basetable_id = models.AutoField(primary_key=True)
    CompanyId = models.IntegerField()


class Cashcashequivalentsrestrictedcashandrestrictedcashequivalents(models.Model):
    cashcashequivalentsrestrictedcashandrestrictedcashequivalents_id = models.AutoField(
        primary_key=True)
    unitRef = models.CharField(max_length=100)
    value = models.CharField(max_length=100)
    decimals = models.IntegerField()
    basetable_id = models.ForeignKey(Basetable, on_delete=models.CASCADE)

当前Serializer定义 #

class CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsSerializer(serializers.ModelSerializer):

    class Meta:
        model = Cashcashequivalentsrestrictedcashandrestrictedcashequivalents
        fields = ['decimals', 'unitRef', 'value']


class CashFlowSerializer(serializers.ModelSerializer):
    CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents = CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsSerializer(
        many=True)

    class Meta:
        model = Basetable
        fields = "__all__"

当前View代码片段 #

.....#TRIMMED GET SYNTAX.....
check = CashFlowSerializer(data=jsonToUse)
if (check.is_valid(raise_exception=True)):
    print("ready to send to db")
    check.save()
return JsonResponse(jsonToUse, safe=False)

解决方案 #

报错原因是：Basetable模型本身没有CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents字段，默认的save()方法会尝试把这个嵌套字段传给Basetable构造函数，导致参数不匹配。需要重写序列化器的create方法，手动处理嵌套数据的保存：

修改Serializer代码 #

class CashFlowSerializer(serializers.ModelSerializer):
    CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents = CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsSerializer(
        many=True)

    class Meta:
        model = Basetable
        fields = "__all__"

    def create(self, validated_data):
        # 取出嵌套的现金数据并从主数据中移除
        cash_data = validated_data.pop('CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents')
        # 创建主表Basetable实例
        basetable = Basetable.objects.create(**validated_data)
        # 遍历嵌套数据，创建关联的子表实例
        for cash_item in cash_data:
            # 将JSON中的字符串类型decimals转为整数，匹配Model字段类型
            cash_item['decimals'] = int(cash_item['decimals'])
            Cashcashequivalentsrestrictedcashandrestrictedcashequivalents.objects.create(
                basetable_id=basetable, **cash_item
            )
        return basetable

额外注意事项 #

• JSON中的decimals是字符串格式（如"-6"），但Model定义为IntegerField，必须手动转换类型，否则会触发类型错误。
• 子表的外键字段basetable_id需要传入Basetable实例，而非ID值。

修改后，调用check.save()会先创建主表数据，再循环创建关联的子表数据，即可完成嵌套JSON的数据库存储。

内容的提问来源于stack exchange，提问作者Maddy