Django Model对象创建

Question

Look at my django model (I'm pasting here only a part of it):

from django.contrib.auth.models import User as DjangoUser
from django.db import models

class Client(DjangoUser):
    address = models.ForeignKey(Address, blank=True, null=True)

I know how to create fresh Client and User:

client = Client(username=name, password=pass)
client.save()

This code creates two records: user and client, client references user with its foreign key.

In my mysql db there is already a DjangoUser record. And now I want to create Client based on this existing user. How to do this?

Answer 1

User is a special case in the Django framework. You should not use inheritance.

The best practice to add data to it is to create a model and define it as user profile :

Create a model for this:

from django.db import models
from django.contrib.auth.models import User

class UserProfile(models.Model):
    user = models.ForeignKey(User, unique=True) # ensure you create one profile only
    address = models.ForeignKey(Address, blank=True, null=True)

Then you should declare it in the settings as the user profile:

AUTH_PROFILE_MODULE = "your_app.UserProfile"

Then in your view:

def your_view(request):
    user_profile = request.user.get_profile()
    address = user_profile.address

This is the standard way to do it because Django contrib apps such as the admin, or auth (with login, permissions, etc) will expect the user to be a User class and not the subclass you are creating.

If you use inheritance, request.user won't be the object you created and you won't be able to access it's data.

If your concern is to be able to edit all data concerning the user in the same page, then there is a way to do this :

Answer 2

You could so something like this:

from django.contrib.auth.models import User as DjangoUser
from django.db import models

class ClientDetails(models.Model):
   user = models.OneToOneField(DjangoUser)
   address = models.ForeignKey(Address, blank=True, null=True)

And your code to create the object would be something like this:

#assuming there is a user with this object already, you should add logic to handle the case when there is no user available.
django_user = DjangoUser.objects.get(username=name)

client = Client(user=django_user, password=pass)
client.save()

Or you could do something like this if you want to extend the User, which isn't normally done. You should use profiles for this.

from django.contrib.auth.models import User as DjangoUser
from django.db import models

class ClientDetails(DjangoUser):
   address = models.ForeignKey(Address, blank=True, null=True)

And then your client code isn't too much different then you described.

#assuming there is a user with this object already, you should add logic to handle the case when there is no user available.
client = Client(username=name, password=pass)
client.save()

Answer 3

User is not abstract, so extending it like that will not work. Rather, you should use composition.

from django.contrib.auth.models import User as DjangoUser
from django.db import models

class ClientDetails(models.Model):
   user = models.OneToOneField(DjangoUser)
   address = models.ForeignKey(Address, blank=True, null=True)

This pattern is documented here: http://docs.djangoproject.com/en/dev/topics/auth/#storing-additional-information-about-users