更新嵌套序列化程序时的 Django rest 框架验证 (many=True)

Question

我有以下型号：

class Child(models.Model):
    attr1 = models.CharField(max_length=20)
    attr2 = models.CharField(max_length=30)
    attr3 = models.BigIntegerField()
    class Meta:
        unique_together = ("attr1", "attr2", "attr3")
class Parent(models.Model):
    children = models.ManyToManyField(Child, related_name="parents")

然后是以下序列化程序：

class ChildSerializer(serializers.ModelSerializer):
    class Meta:
        model = Child
class ParentSerializer(serializers.ModelSerializer):
    children = ChildSerializer(many=True)
    class Meta:
        model = Parent

使用嵌套 （many=True） 子序列化程序更新父实例时，出现验证错误：

The fields attr1, attr2, attr3 must make a unique set.

但是，序列化程序是否应该跳过对子项的验证，因为它们已经从数据库中检索到的实例？

Answer 1

Nested Serializers对

我有用many=true.这是我的代码：

class ChildSerializer(serializers.ModelSerializer):
    parents = ChildSerializer(many=True)
    class Meta:
        model = Child
        fields = ('id', 'parents')
class ParentSerializer(serializers.ModelSerializer):
    class Meta:
        model = Parent

父模型包含子字段。在序列化程序中，您尝试在其中添加相同的字段。正因为如此，它说字段必须是唯一的。

Answer 2

可以通过重写 ParentSerialzer 的to_internal_value来"跳过"子序列化程序验证，或编写自定义序列化程序验证以重写子序列化程序：

class ParentSerializer(serializers.ModelSerializer):
    children = ChildSerializer(many=True)
    def to_internal_value(self, *args, **kwargs):
        try:
            # runs the child serializers
            return super().to_internal_value(*args, **kwargs)
        except ValidationError as e:
            # fails, and then overrides the child errors with the parent error
            return self.validate(self.initial_data)
    def validate(self, attrs):
        errors = {}
        errors['custom_override_error'] = 'this ignores, and overrides the children serializers'
        if len(errors):
            raise ValidationErrors(errors)
        return attrs
    class Meta:
        model = Parent