Django抽象模型无法实例化求助：使用djongo ArrayField报错

创建了MailGroup和Recipient两个模型，将Recipient的abstract属性设为True。当执行mailGroups = MailGroup.objects.all()获取MailGroup对象列表时，抛出如下错误：

TypeError: Abstract models cannot be instantiated.

涉及代码文件 #

models.py #

from djongo import models

class Recipient(models.Model):
    recipientName = models.CharField(max_length=255, null = False)
    recipientMailId = models.EmailField(max_length = 255, unique = True, null = False)

    class Meta:
        abstract = True


class MailGroup(models.Model):
    mailGroupName = models.CharField(max_length = 255, unique = True, null = False)
    recipients = models.ArrayField(
        model_container = Recipient
    )

    class Meta:
        abstract = False

serializers.py #

from rest_framework import serializers
from dashboardServer.models import MailGroup

class MailGroupSerializer(serializers.ModelSerializer):
    class Meta:
        model = MailGroup
        fields = ["id", "mailGroupName", "recipients"]

views.py #

@api_view(["GET", "POST", "PATCH", "DELETE"])
def mailGroupsView(request):

    if request.method == "GET":
        mailGroups = MailGroup.objects.all() # 此处抛出上述错误
        serializer = MailGroupSerializer(mailGroups, many = True)
        return JsonResponse({
            "status": "success",
            "info": "Mail groups fetched successfully",
            "title": "Success",
            "data": serializer.data
        }, status = 200)

当前使用版本：Django 4.1.9、sqlparse 0.2.4、djongo 1.3.6

解决方案 #

错误核心原因：Django禁止实例化抽象模型，而djongo在处理ArrayField的model_container参数时，会尝试创建对应模型的实例来封装数据库读取的嵌套数据，因此使用抽象模型Recipient会触发报错。

方法一：将Recipient改为非抽象模型（推荐） #

移除Recipient模型中的abstract = True，同时设置managed = False避免Django为其创建单独的MongoDB集合：

class Recipient(models.Model):
    recipientName = models.CharField(max_length=255, null=False)
    recipientMailId = models.EmailField(max_length=255, unique=True, null=False)

    class Meta:
        managed = False  # 不生成单独集合，仅作为嵌套文档的模型定义

方法二：改用DictField配合自定义序列化验证 #

如果不想用模型定义嵌套结构，可将MailGroup的recipients改为DictField，再在序列化器中手动定义字段验证规则：

1. 修改models.py：

class MailGroup(models.Model):
    mailGroupName = models.CharField(max_length=255, unique=True, null=False)
    recipients = models.ArrayField(
        model_container=models.DictField()
    )

2. 修改serializers.py，添加嵌套序列化器：

from rest_framework import serializers
from dashboardServer.models import MailGroup

class RecipientSerializer(serializers.Serializer):
    recipientName = serializers.CharField(max_length=255, required=True)
    recipientMailId = serializers.EmailField(max_length=255, required=True)

class MailGroupSerializer(serializers.ModelSerializer):
    recipients = RecipientSerializer(many=True)
    class Meta:
        model = MailGroup
        fields = ["id", "mailGroupName", "recipients"]

内容的提问来源于stack exchange，提问作者Daniel Vanum