Question

“ post_id”列不能为空

我不知道为什么我不能携带post_id。如果您尝试添加评论，则可能无法携带post_id。我解决不了请帮助我。

models.py


class Comment(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    post = models.ForeignKey(Post, on_delete=models.CASCADE)

serializers.py


class CommentSerializer(serializers.ModelSerializer):
    user = UserSerializer(read_only=True)
    post = PostSerializer(read_only=True)

    class Meta:
        model = Comment
        fields = (
            'user',
            'post',
            'id',
            'content',
        )
        read_only_fields = ('created_at',)

views.py

# api/views.py


class CommentView(viewsets.ModelViewSet):
    queryset = Comment.objects.all()
    serializer_class = CommentSerializer
    permission_classes = (permissions.IsAuthenticated,)
    def perform_create(self, serializer):
        serializer.save(user=self.request.user)

Answer 1

用下面的代码替换您的代码。

class Comment(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE, null=True)
    post = models.ForeignKey(Post, on_delete=models.CASCADE, null=True)

替换代码后，进行迁移，然后重试

Answer 2

Comment模型与Post模型具有外键关系。因此，如果创建新注释，则必须设置Post（post_id）的值。您可以在序列化器中或在视图集中的perform_create方法中执行此操作。

在下面的示例中，我假设值为post id的字段的名称为post。而且我没有为要检索的帖子添加验证。

示例：

class CommentSerializer(serializers.ModelSerializer):
    user = UserSerializer(read_only=True)
    post = PostSerializer(read_only=True)

    def create(self, validated_data):
        instance = super().create(validated_data)
        instance.post = Post.objects.get(id=self.initial_data['post'])
        instance.save()

        return instance

    class Meta:
        model = Comment
        fields = (
        'user',
        'post',
        'id',
        'content',
        )
        read_only_fields = ('created_at',)

列“ post_id”不能为空

2 个答案: