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django - Django rest IntegrityError：1048，外键序列化程序上的“列不能为空”

问题描述

我的模型定义如下：

class Responsibility(models.Model):
    name = models.CharField(max_length=50, blank=True, null=True, )

class Collaborator(models.Model):
    name = models.CharField(max_length=50, blank=True, null=True, )


class Card(models.Model):
    thing = models.CharField(max_length=50, blank=True, null = True, )
    responsibilities = models.ForeignKey(Responsibility, related_name='res_cards', blank=True, on_delete=models.CASCADE)
    collaborators = models.ForeignKey(Collaborator, related_name='col_cards', blank=True, on_delete=models.CASCADE)

和序列化器：

class CollaboratorSerializer(serializers.ModelSerializer):

    class Meta:
        model = Collaborator
        fields = '__all__'

class ResponsibilitySerializer(serializers.ModelSerializer):
    class Meta:
        model = Responsibility
        fields = '__all__'      


class CardSerializer(serializers.ModelSerializer):
    responsibilities = ResponsibilitySerializer(many=True,)
    collaborators = CollaboratorSerializer(many=True,)

    class Meta:
        model = Card
        fields = '__all__'

    def create(self, validated_data):
        responsibilities_data = validated_data.pop('responsibilities')
        collaborators_data = validated_data.pop('collaborators')

        card = Card.objects.create(**validated_data)
        for responsibility_data in responsibilities_data:
            Responsibility.objects.create(card=card, **track_data)
        for collaborator_data in collaborators_data:
            Collaborator.objects.create(card=card, **track_data)
        return card

我的 POST 请求如下所示：

{u'thing': u'Book', u'responsibilities': [{u'name': u'Name'}, {u'name': u'ISBN'}], u'collaborators': [{u'name': u''}]}

但应用程序抛出上述错误。我错过了什么？职责和协作者并不预先存在，它们将与 Card 一起创建，也应该与 Card 一起更新，而不是独立更新。

更新：我对 GET 和 POST 的看法

@api_view(['GET', 'POST'])
def card_list(request):
    """
    List all tasks, or create a new card
    """
    if request.method == 'GET':
        cards = Card.objects.all()
        serializer = CardSerializer(cards, many=True)
        return Response(serializer.data)

    elif request.method == 'POST':
        print(request.data)
        serializer = CardSerializer(data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        else:
            return Response(
                serializer.errors, status=status.HTTP_400_BAD_REQUEST)

标签： djangodjango-rest-framework

解决方案

这里可能会出现错误：card = Card.objects.create(**validated_data)- 当您尝试创建Card条目时；Django 期望Responsbility和Collaborator外键作为validated_data. 这是因为您的架构的定义方式；外键不为空；Card因此，如果没有这两个ForeignKey条目，您将无法创建 a 。更改您的Card模型以允许 nullresponsibilities和collaborators

class Card(models.Model):
    thing = models.CharField(max_length=50, blank=True, null = True, )
    responsibilities = models.ForeignKey(Responsibility, related_name='res_cards', blank=True, null=True, on_delete=models.CASCADE)
    collaborators = models.ForeignKey(Collaborator, related_name='col_cards', blank=True, null=True, on_delete=models.CASCADE)

如果更改架构不是一种选择；反转方法中的操作顺序create：

for responsibility_data in responsibilities_data:
    resp = Responsibility.objects.create(**responsibility_data)
for collaborator_data in collaborators_data:
    collab = Collaborator.objects.create(**collaborator_data)
validated_data.update({responsibilities: resp.pk, 'collaborators': collab.pk})
card = Card.objects.create(**validated_data)

从您的问题来看，您似乎需要将一张卡与多个职责和合作者相关联。您应该将外键移动到其他表（resp 和 colllab）以指向卡片，而不是从卡片向前指向。

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