Django/石墨烯突变错误“；您需要传递一个有效的Django模型；can'；我修不好

下面是我正在使用的Django/石墨烯示例的RDBMS图：

以下是应用程序my model.py的代码：

from django.db import models

# Create your models here.
class ProductCategory(models.Model):
  category = models.CharField(max_length=50)
  parentCategory = models.ForeignKey('self',null=True, on_delete=models.CASCADE)

class Product(models.Model):
  productNumber= models.CharField(max_length=50)
  description = models.CharField(max_length=50)
  productCategory= models.ForeignKey('product.ProductCategory', on_delete=models.PROTECT)

import graphene
from graphene_django import DjangoObjectType

from .models import Product, ProductCategory

class ProductType(DjangoObjectType):
  class Meta:
    model = Product

class ProductCategoryType(DjangoObjectType):
  class Meta:
    model = ProductCategory

class Query(graphene.ObjectType):
  products = graphene.List(ProductType)
  productCategories = graphene.List(ProductCategoryType)

  def resolve_products(self, info):
      return Product.objects.all()
  def resolve_productCategories(self,info):
      return ProductCategory.objects.all()


class CreateProductCategory(DjangoObjectType):
  productCategory = graphene.Field(ProductCategoryType)

  class Arguments:
    category = graphene.String(required=True)
    parentCategory = graphene.Int()
  
  def mutate(self, info, category, parentCategory):
    productCategory = ProductCategory(category = category, parentCategory = parentCategory)
    productCategory.save()
    return CreateProductCategory(productCategory=productCategory)

    return CreateProductCategory(category=category,parentCategory=parentCategory)

class Mutation(graphene.ObjectType):
  createProductCategory= CreateProductCategory.Field()

下面是应用程序的Schema.py：

from django.db import models

# Create your models here.
class ProductCategory(models.Model):
  category = models.CharField(max_length=50)
  parentCategory = models.ForeignKey('self',null=True, on_delete=models.CASCADE)

class Product(models.Model):
  productNumber= models.CharField(max_length=50)
  description = models.CharField(max_length=50)
  productCategory= models.ForeignKey('product.ProductCategory', on_delete=models.PROTECT)

import graphene
from graphene_django import DjangoObjectType

from .models import Product, ProductCategory

class ProductType(DjangoObjectType):
  class Meta:
    model = Product

class ProductCategoryType(DjangoObjectType):
  class Meta:
    model = ProductCategory

class Query(graphene.ObjectType):
  products = graphene.List(ProductType)
  productCategories = graphene.List(ProductCategoryType)

  def resolve_products(self, info):
      return Product.objects.all()
  def resolve_productCategories(self,info):
      return ProductCategory.objects.all()


class CreateProductCategory(DjangoObjectType):
  productCategory = graphene.Field(ProductCategoryType)

  class Arguments:
    category = graphene.String(required=True)
    parentCategory = graphene.Int()
  
  def mutate(self, info, category, parentCategory):
    productCategory = ProductCategory(category = category, parentCategory = parentCategory)
    productCategory.save()
    return CreateProductCategory(productCategory=productCategory)

    return CreateProductCategory(category=category,parentCategory=parentCategory)

class Mutation(graphene.ObjectType):
  createProductCategory= CreateProductCategory.Field()

如果没有变异代码，查询请求可以正常工作，如下所示

但当添加变异代码时，它会输出一个错误，我无法找出我做错了什么，因为我是一个noob。请帮忙

---

AssertionError:您需要在CreateProductCategory.Meta中传递一个有效的Django模型，收到“无”。这就是问题所在：

类CreateProductCategory（DjangObjectType）

对于突变，您需要继承

graphene.Mutation

，而不是

djangObjectType

正确：

class CreateProductCategory（graphene.Mutation）

---

`

这是否回答了您的问题？谢谢它就像一个符咒。