Extending the existing User model

There are two ways to extend the default User model without substituting your own model. If the changes you need are purely behavioral, and don’t require any change to what is stored in the database, you can create a proxy model based on User. This allows for any of the features offered by proxy models including default ordering, custom managers, or custom model methods.

★ 兩種方式擴充套件預設的 User。如果你需要增加的功能僅僅是形式上的，而不需要任何對資料庫存放的資料的改變，那麼可以使用代理模式。如此可以利用代理模式提供的任何便利，包括預設順序，定製的 Manager，定製的 model 方法等等。

If you wish to store information related to User, you can use a one-to-one relationship to a model containing the fields for additional information. This one-to-one model is often called a profile model, as it might store non-auth related information about a site user. For example you might create an Employee model:

★ 如果想儲存和 User 有關的資訊，可以使用 one-to-one relationship，關聯一個有額外資訊的模組上。這種一對一的模組通常被稱作“側寫”模組，它存放的可能是和許可權無關的User的資訊。比如下面的例子：

from django.contrib.auth.models import User

class Employee(models.Model):
    user = models.OneToOneField(User)
    department = models.CharField(max_length=100)

Assuming an existing Employee Fred Smith who has both a User and Employee model, you can access the related information using Django’s standard related model conventions:

>>> u = User.objects.get(username='fsmith')
>>> freds_department = u.employee.department

To add a profile model’s fields to the user page in the admin, define an InlineModelAdmin (for this example, we’ll use a StackedInline) in your app’s admin.py and add it to a UserAdmin class which is registered with the User class:   ★ 為 admin 裡的 user 頁面增加側寫模組裡的屬性資訊，要定義 InlineModelAdmin（例如，使用 StackedInline），並把它新增到為User類提供支援的 UserAdmin 類裡。

from django.contrib import admin
from django.contrib.auth.admin import UserAdmin
from django.contrib.auth.models import User

from my_user_profile_app.models import Employee

# Define an inline admin descriptor for Employee model
# which acts a bit like a singleton
class EmployeeInline(admin.StackedInline):
    model = Employee
    can_delete = False
    verbose_name_plural = 'employee'

# Define a new User admin
class UserAdmin(UserAdmin):
    inlines = (EmployeeInline, )

# Re-register UserAdmin
admin.site.unregister(User)
admin.site.register(User, UserAdmin)

These profile models are not special in any way - they are just Django models that happen to have a one-to-one link with a User model. As such, they do not get auto created when a user is created, but a django.db.models.signals.post_save could be used to create or update related models as appropriate.

★ 側寫模組沒有任何特殊之處，他們只是擁有和User 模組一對一關係的 Django 模組。因此，當 user 被建立時側寫資訊不會自動生成，使用 django.db.models.signals.post_save 方法可以建立或更新相關的模組。 

Note that using related models results in additional queries or joins to retrieve the related data, and depending on your needs substituting the User model and adding the related fields may be your better option. However existing links to the default User model within your project’s apps may justify the extra database load.

★ 要注意的是，使用相關的模組導致增加了額外的查詢和額外的檢索程式碼，並且取決於要替代 User 模組的需求的型別，增加額外的 fields 或許是更好的選擇。 

Deprecated since version 1.5: With the introduction of custom User models, the use of AUTH_PROFILE_MODULE to define a single profile model is no longer supported. See the Django 1.5 release notes for more information.

★ 這個功能在 v1.5 時已經廢棄了 

Prior to 1.5, a single profile model could be specified site-wide with the setting AUTH_PROFILE_MODULE with a string consisting of the following items, separated by a dot:

1. The name of the application (case sensitive) in which the user profile model is defined (in other words, the name which was passed to manage.py startapp to create the application).
2. The name of the model (not case sensitive) class.

For example, if the profile model was a class named UserProfile and was defined inside an application named accounts, the appropriate setting would be:

AUTH_PROFILE_MODULE = 'accounts.UserProfile'

When a user profile model has been defined and specified in this manner, each User object will have a method – get_profile() – which returns the instance of the user profile model associated with that User.

The method get_profile() does not create a profile if one does not exist.