django manytomany通过 [英] django manytomany through

问题描述

如果我有两个模型与一个通过模型有很多关系，那么我如何从通过表中获取数据。

  class Bike（models.Model）：
 nickname = models.CharField（max_length = 40）
 users = models.ManyToManyField（User，through ='bike.BikeUser'）
  

BikeUser类

  class BikeUser（models.Model）：
 bike = models.ForeignKey（Bike）
 user = models.ForeignKey（User）
 comment = models.CharField（max_length = 140）
  

我会添加一个用户到那辆自行车（假设我有一个myBike和一个myUser已经） >

  BikeUser.objects.create（bike = myBike，user = myUser，comment ='在一个花哨的商店获得这个）
我可以通过myBike.users.all（）获取所有的用户，但是如何获得'comment'property？
 
 
 
我想做某事喜欢myBike.users.all（）：
打印myBikeUser.comment 
 
  code> 
 
 
解决方案
通过表与标准ForeignKeys链接，所以你做一个普​​通的ForeignKey查找。不要忘记每个自行车用户有一个评论，也就是每个自行车/用户配对的评论。 myBike.bikeuser_set.all（）中的myBikeUser 
 
 
 打印myBikeUser.comment，myBikeUser.user.first_name 
  
 
If I have two Models that have a manytomany relationship with a through model, how do I get data from that 'through' table.
class Bike(models.Model):
   nickname = models.CharField(max_length=40)
   users    = models.ManyToManyField(User, through='bike.BikeUser')
The BikeUser class
class BikeUser(models.Model):
   bike     = models.ForeignKey(Bike)
   user     = models.ForeignKey(User)
   comment  = models.CharField(max_length=140)
And I would add a user to that bike (presuming I have a myBike and a myUser already)
BikeUser.objects.create(bike = myBike, user = myUser, comment = 'Got this one at a fancy store')
I can get all the users on 'myBike' with myBike.users.all() but how do I get the 'comment' property?


I would like to do something like
for myBikeUser in myBike.users.all():
   print myBikeUser.comment

解决方案
The through table is linked by standard ForeignKeys, so you do a normal ForeignKey lookup. Don't forget that there's a comment for each bikeuser, ie one for each bike/user pairing. 
for myBikeUser in myBike.bikeuser_set.all():
    print myBikeUser.comment, myBikeUser.user.first_name


                        
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