python - 无法从另一个 python 代码访问 ListField 元素

Question

您好，我想使用一个名为 common 的应用程序在两个 django 应用程序(监视器、管理器)之间共享一个 mongodb。

我可以轻松地在管理器应用程序中创建数据库实例，但是在访问图书作者时我不能。

它返回这个错误

mongoengine.errors.FieldDoesNotExist: The fields "{'_id'}" do not exist on the document "author"

模型.py

from mongoengine import *

class author(Document):
   name = StringField(required = True)
   meta = {'abstract': True , 'allow_inheritance':True}


class book(Document):
   name = StringField(required = True)
   authors = ListField(ReferenceField(author))
   meta = {'abstract': True , 'allow_inheritance':True}

管理器.py

from mongoengine import * 
from models import * 

class author(author):
    def rand(self):
        print("i am useless")
class book(book):
    def rand2(self):
        print("i am also useless")


if __name__ == "__main__":
    connect('test', host = '0.0.0.0',port = 27017)
    a1 = author(name = "Charef")
    a1.save()
    a2 = author(name = "hamid")
    a2.save()
    a3 = author(name = "djoudi")
    a3.save()
    a4 = author(name = "cheb khaled")
    a4.save()
    book1_authors = [a1,a2,a4]
    book2_authors = [a1,a3]


    book1 = book(name = "Hello Django", authors = book1_authors)
    book1.save()

    book2 = book(name = "Hello python", authors = book2_authors)
    book2.save()

监控

from mongoengine import * 
from models import * 

class author(author):
    def say_hi(self):
        print("Hi, my name is {} and this is my book".format(self.name))

class book(book):
    def book_info(self):
        for author in self.authors:
            print(author.say_hi())
            print("done !! ")



if __name__ == "__main__":
    connect("test",host = "0.0.0.0", port = 27017)
    s_book = book.objects()[0]
    print(s_book.name)
    print(len(s_book.authors))

Answer 1

为不同的类使用唯一的名称(例如，BaseBook 用于抽象类，Book 用于具体类)。 mongoengine 的一些内部结构依赖于类名的唯一性，因此反对它不是一个好主意。

使用以下作品:

class BaseAuthor(Document):
   name = StringField(required=True)
   meta = {'abstract': True , 'allow_inheritance':True}


class BaseBook(Document):
   name = StringField(required=True)
   authors = ListField(ReferenceField(BaseAuthor))
   meta = {'abstract': True , 'allow_inheritance':True}

class Author(BaseAuthor):
    def rand(self):
        print("i am useless")

class Book(BaseBook):
    def rand2(self):
        print("i am also useless")

此外，如果可能的话，在监视器和管理器中使用相同的 Book/Author 类