# coding:utf8
from django.db import models

class Book(models.Model):
  
  name = models.CharField(max_length=255)
  title = models.CharField(max_length=255)
  price = models.IntegerField()
  ...
  
class Category(models.Model):
  
  CATEGORY_CHOICES = (
    ('00', 'English'),
    ('01', 'Computer'),
  )
  
  book = models.ForeignKey(Book)
  category = models.CharField(max_length=255, choices=CATEGORY_CHOICES)
  remark = models.CharField(max_length=255)
  ...

# coding: utf8
from django.contrib import admin
from django import forms

from .models import Category

class CategoryAdmin(admin.ModelAdmin):

  search_fileds = ('book__name', 'book__title', 'book__price', 'category') # 设置搜索栏范围，如果有外键，要注明外键的哪个字段，双下划线
  list_display = ('book', 'category') # 在页面上显示的字段，若不设置则显示 models.py 中 __unicode__(self) 中所返回的值
  list_display_links = ('category') # 设置页面上哪个字段可单击进入详细页面
  fields = ('category', 'book') # 设置添加/修改详细信息时，哪些字段显示，在这里 remark 字段将不显示
  
admin.site.register(Category, CategoryAdmin)

class A:
   name=models.CharField(max_length=15)
   def __unicode__(self):
       return self.name
 
class B:
   name=models.CharField(max_length=15)
   f=models.ForeignKey(A,on_delete=models.DO_NOTHING)
 
   def __unicode__(self):
      return self.name

class A:
   name=models.CharField(max_length=15)
   def __str__(self):
       return self.name
 
class B:
   name=models.CharField(max_length=15)
   f=models.ForeignKey(A,on_delete=models.DO_NOTHING)
 
   def __str__(self):
      return self.name

from django.utils.encoding import python_2_unicode_compatible
 
@python_2_unicode_compatible
class A:
   name=models.CharField(max_length=15)
   def __str__(self):
       return self.name
 
@python_2_unicode_compatible
class B:
   name=models.CharField(max_length=15)
   f=models.ForeignKey(A,on_delete=models.DO_NOTHING)
 
   def __str__(self):
      return self.name