用戶配置（USER_ID = 2）返回<用戶配置：用戶>，但用戶配置（USER_ID = 2）.birth_year返回None

Question

我有以下模型，並正嘗試在django shell這兩個命令：

1. from auth_lifecycle.models import UserProfile
2. UserProfile(user_id=2).birth_year

但它的返回None，儘管UserProfile(user_id=2)返回<UserProfile: user>。

這裏是查詢確認數據是否存在：

auth_lifecycle_db=# select * from auth_lifecycle_userprofile; 
    id | birth_year | user_id 
----+------------+--------- 
    1 |  1905 |  1 
    2 |  1910 |  2 
(2 rows) 

如何訪問birth_year屬性？

---

models.py

"""Defines a single extra user-profile field for the user-authentication 
    lifecycle demo project: Birth year 
""" 
from django.contrib.auth.models import User 
from django.db     import models 


class UserProfile(models.Model): 
    """Extra information about a user: Birth year and profile picture. See 
     the package doc for more info. 

     ---NOTES--- 

     Useful related SQL: 
      - `select id from auth_user where username <> 'admin';` 
      - `select * from auth_lifecycle_userprofile where user_id=(x,x,...);` 
    """ 
    # This line is required. Links UserProfile to a User model instance. 
    user = models.OneToOneField(User, related_name="profile") 

    # The additional attributes we wish to include. 
    birth_year = models.IntegerField(
     blank=True, 
     verbose_name="Year you were born") 

    # Override the __str__() method to return out something meaningful 
    def __str__(self): 
     return self.user.username 

Answer 1

您需要使用objects屬性來訪問數據庫值。

UserProfile.objects.get(user_id=2).birth_year 

或

User.objects.get(id=2).profile.birth_year 

所有的代碼確實是創造UserProfile本地實例與user_id=2

https://docs.djangoproject.com/en/1.7/topics/db/models/#model-attributes