python - Django:manage.py loaddata 返回 'Deserialization Error'

Question

因此，当我尝试从 cmd 将数据从 .json 文件加载到模型中时，出现以下错误:

这似乎是“category_id”的问题，但我不确定如何解决这个问题。

这是我的代码:

shop/models.py

from django.db import models
from django.urls import reverse


# Create your models here.
class Category(models.Model):
    name = models.TextField()  
    products = models.ManyToManyField('Product')

    def get_products(self):
        return Product.objects.filter(category=self)

    def __str__(self):
        return self.name 

    def get_absolute_url(self):
        return reverse('product_list_by_category',args=[self.id])


class Product(models.Model):
    name = models.TextField()
    description = models.TextField()
    stock = models.IntegerField()
    price = models.DecimalField(max_digits=10,decimal_places=2)
    image = models.ImageField(upload_to='images/', blank=True)

    def __str__(self):
        return self.name

商店/views.py

from django.shortcuts import render, get_object_or_404, redirect
from .models import Category, Product
from django.db.models import Count
from django.contrib.auth.models import Group, User
from django.core.paginator import Paginator, EmptyPage, InvalidPage

def product_list(request, category_id=None):
    category = None
    products = Product.objects.all()
    ccat = Category.objects.annotate(num_products=Count('products'))
    if category_id:
        category = get_object_or_404(Category, id=category_id)
        products = products.filter(category=category)
    paginator = Paginator(products, 3)
    try:
        page = int(request.GET.get('page', 1))
    except:
        page = 1
    try:
        products = paginator.page(page)
    except(EmptyPage, InvalidPage):
        products = paginator.page(paginator.num_pages)

    return render(request, 'products.html',
                    {'products': products,
                    'countcat':ccat})

这是我希望加载到数据库中的两个 .json 文件(值得注意的是 createcategories.json 工作没有问题)

创建类别.json

[
    {
        "model": "shop.category",
        "pk": 1,
        "fields": {
            "name": "Europe"
        }
    },
    {
        "model": "shop.category",
        "pk": 2,
        "fields": {
            "name": "North America"
        }
    },
    {
        "model": "shop.category",
        "pk": 3,
        "fields": {
            "name": "South America"
        }
    },
    {
        "model": "shop.category",
        "pk": 4,
        "fields": {
            "name": "Asia"
        }
    },
    {
        "model": "shop.category",
        "pk": 5,
        "fields": {
            "name": "Africa"
        }
    },
    {
        "model": "shop.category",
        "pk": 6,
        "fields": {
            "name": "Middle East"
        }
    }
]

I thought that the category_id would get added automatically as a foreign key bu it has not.

Many thanks in advance!

创建产品.json

[
    {
      "model": "shop.product",
      "pk": 1,
      "fields": {
        "category_id":1,
        "name": "Europe Title 1",
        "description": "Europe Description 1",
        "stock": 3,
        "price": 100.00
        }
    },
    {
        "model": "shop.product",
        "pk": 2,
        "fields": {
          "category_id":2,
          "name": "North America Title 1",
          "description": "North America Description 1",
          "stock": 4,
          "price": 7.00
          }
      },
      {
        "model": "shop.product",
        "pk": 3,
        "fields": {
          "category_id":3,
          "name": "South America Title 1",
          "description": "South America Desc 1",
          "stock": 100,
          "price": 2.00
          }
      },
      {
        "model": "shop.product",
        "pk": 4,
        "fields": {
          "category_id":4,
          "name": "Asia Title 1",
          "description": "Asia Desc 1",
          "stock": 50,
          "price": 1.00
          }
      },
      {
        "model": "shop.product",
        "pk": 5,
        "fields": {
          "category_id":5,
          "name": "Africa Title 1",
          "description": "Africa Desc 1",
          "stock": 9,
          "price": 99.00
          }
      },
      {
        "model": "shop.product",
        "pk": 6,
        "fields": {
          "category_id":4,
          "name": "Asia Title 2",
          "description": "Asia Desc 2",
          "stock": 1,
          "price": 50.00
          }
      },
      {
        "model": "shop.product",
        "pk": 7,
        "fields": {
          "category_id":1,
          "name": "Europe Title 2",
          "description": "Europe Desc 2",
          "stock": 2,
          "price": 300.00
          }
      },
      {
        "model": "shop.product",
        "pk": 8,
        "fields": {
          "category_id":4,
          "name": "Asia Title 3",
          "description": "Asia Desc 3",
          "stock": 2,
          "price": 75.00
          }
      },
      {
        "model": "shop.product",
        "pk": 9,
        "fields": {
          "category_id":6,
          "name": "Middle East Title 1",
          "description": "Middle East Desc 1",
          "stock": 1,
          "price": 50.00
          }
      },
      {
        "model": "shop.product",
        "pk": 10,
        "fields": {
          "category_id":6,
          "name": "Middle East Title 2",
          "description": "Middle East Desc 1",
          "stock": 2,
          "price": 15.00
          }
      }
]

Answer 1

而不是 category_id在createproducts.json ，你应该有products在createcategories.json .

我的猜测是，当创建转储时，有一个 ForeignKey关系来自Product至Category ，但现在有一个 ManyToMany关系来自Category至Product .

如果您可以在没有类别分配的情况下生存，则可以删除 category_id条目。否则你必须重写这两个文件。