尝试在Django中关联表

Question

尝试POST请求并创建新位置。现在，字段country_id暗示了许多麻烦。这些是类

class Country(models.Model):
id = UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
country_name = CharField(max_length=255)
federal_rate = FloatField()
social_security = FloatField()
comment = CharField(max_length=255)
class Location(models.Model):
participant_id = ForeignKey('Participant', on_delete=CASCADE, related_name="locations")
country_id = ForeignKey('Country', on_delete=CASCADE, related_name="country")
start_date = DateField()
end_date = DateField()
region = CharField(max_length=255)
tax_policy = CharField(max_length=255, null=True)

序列化器

class CountrySerializer(serializers.ModelSerializer):
class Meta:
model = Country
fields = "__all__"
class LoactionSerializer(serializers.ModelSerializer):
country_id = CountrySerializer(many=False)
class Meta:
model = Location
fields = "__all__"

现在我成功连接表的唯一原因是在序列化器中添加country_id行，当我试图创建新位置时，会发生错误这是我尝试添加新位置的方式

{
"start_date": "2021-10-10",
"end_date": "2021-11-18",
"region": "markian-land",
"tax_policy": "N/A",
"participant_id": "c5c1a00c-4263-418a-9f3a-3ce40a1ea334",
"country_id": "9067e71f-c6b9-4ecc-ad6b-461843063aee"
}

错误- {"country_id": {"non_field_error ": ["无效数据。期望得到字典，但得到str."]}}

当我还是想送东西,但我有另一个错误,要求所有国家领域,所以我从数据库获取特定国家,当我发送它,我得到json误差

Answer 1

你可以在这个答案中了解更多细节

不提供此功能，您需要先创建一个序列化器字段。

from rest_framework import serializers

class RelatedFieldAlternative(serializers.PrimaryKeyRelatedField):
def __init__(self, **kwargs):
self.serializer = kwargs.pop('serializer', None)
if self.serializer is not None and not issubclass(self.serializer, serializers.Serializer):
raise TypeError('"serializer" is not a valid serializer class')
super().__init__(**kwargs)
def use_pk_only_optimization(self):
return False if self.serializer else True
def to_representation(self, instance):
if self.serializer:
return self.serializer(instance, context=self.context).data
return super().to_representation(instance)

在Location中使用这个新的序列化器字段序列化器,

class LoactionSerializer(serializers.ModelSerializer):
country_id = RelatedFieldAlternative(queryset = Country.objects.all(),
serializer=CountrySerializer)
class Meta:
model = Location
fields = "__all__"

请注意:您在LoactionSerializer中有一个错字。

Answer 2

this

country_id = ForeignKey(Country, on_delete=CASCADE, related_name="country")

Answer 3

您在LocationSerializer中定义了country_id作为CountrySerializer，而在CountrySerializer中，fields = "__all__"意味着您需要传递所有国家对象字段才能使其工作。

尝试删除LocationSerializer中的country_id = CountrySerializer(many=False)，然后重试。