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Django admin save inline form instances with no fields

I'm attemping to add copies of a book through a books admin page.
Inside models.py I have:
class Book(models.Model):
...
class BookCopy(models.Model):
book = models.ForeignKey(
'Book',
related_name='copies',
on_delete=models.CASCADE
)
# No additional fields here
class BookCopyInline(admin.StackedInline):
model = BookCopy
can_delete = False
verbose_name_plural = 'copies'
Inside admin.py I have the following:
class BookCopyInline(admin.StackedInline):
model = BookCopy
can_delete = False
verbose_name_plural = 'copies'
#admin.register(Book)
class BookAdmin(admin.ModelAdmin):
inlines = (BookCopyInline,)
#admin.register(Book)
class BookAdmin(admin.ModelAdmin):
model = Book
list_display = ('isbn', 'title', 'subtitle')
prepopulated_fields = {'slug': ('title',)}
inlines = (BookCopyInline,)
I'd like to be able to add book copies inside the Books Admin page. But since the BookCopy model defines no additional fields the instances are never saved.
Adding a field to BookCopy and filling that in each time allows BookCopies to be created as normal, but I don't require any additional fields right now.
The image below demonstrates the issue I'm facing, new rows can be added, but when save is clicked, no BookCopies are created
Is there a way to have the admin save the instances regardless?

Django rest framework displaying specific field of a model

In my model:
from django.contrib.auth.models import User
class Restaurant(models.Model):
manager = models.ForeignKey(User, on_delete=models.PROTECT,
null=True, blank=False, related_name="manager")
in my serializers.py
class RestaurantSerializer(CoreHyperlinkedModelSerializer):
class Meta:
model = Restaurant
in my views.py
class RestaurantViewSet(viewsets.ModelViewSet):
queryset = Restaurant.objects.order_by('id').all()
serializer_class = RestaurantSerializer
on my list:
the manager is displaying as <rest_framework.relations.PKOnlyObject object at 0x9f7040xbc208>
How can I display it as normal data like its username?

You want to use a 'SlugRelatedField'.

There are a few ways you can go, but if you just want to show a username, all you need is this
from rest_framework import serializers
class RestaurantSerializer(serializers.ModelSerializer):
manager = serializers.CharField(source="manager.username")
class Meta:
model = Restaurant
if you inherit from ModelSerializer and skip the manager field, it will use user PK as the value of the manager field by default.
a slightly more involved way would be to define a separate serializer for User and then embed it in RestaurantSerializer.
from rest_framework import serializers
class UserSerializer(serializers.ModelSerializer):
class Meta:
model = User
class RestaurantSerializer(serializers.ModelSerializer):
manager = UserSerializer()
class Meta:
model = Restaurant
And if you really want to use hyperlinked serializer, you need to do quite a bit of work. You need to read this part carefully http://www.django-rest-framework.org/api-guide/serializers/#how-hyperlinked-views-are-determined

Django Admin Inlines With OneToOne Field

Here in my model, you can see that I have a SpecializedProfile with a OneToOne relationship with a UserProfile, with a OneToOne relationship with the django user model.
I want to create an admin for the SpecializedProfile containing inlines for the UserProfile and the django User model, so that I can create a SpecializedProfile all at once, without needing to go to the UserProfile page and the User page.
Here is my model:
class UserProfile(models.Model):
user_auth = models.OneToOneField(User, related_name="profile", primary_key=True)
# more fields...
class SpecializedProfile(models.Model):
profile = models.OneToOneField(UserProfile, related_name="specialized_profile", primary_key=True)
# More fields...
and here is my attempt at creating the admin:
class UserInline(admin.TabularInline):
model = User
fk_name = 'profile__specialized_profile'
class ProfileInline(admin.TabularInline):
model = UserProfile
fk_name = 'specialized_profile'
class SpecializedProfileAdmin(admin.ModelAdmin):
model = SpecializedProfile
inlines = [
UserInline, ProfileInline
]
admin.site.register(SpecializedProfile, SpecializedProfileAdmin)
The admin isn't working, and I am getting this error:
<class 'profiles.admin.ProfileInline'>: (admin.E202) 'profiles.UserProfile' has no field named 'trainer'.
<class 'profiles.admin.UserInline'>: (admin.E202) 'auth.User' has no ForeignKey to 'profiles.SpecializedProfile'.
It seems like django wants the inlines to be on the models where the OneToOne fields are defined, and won't accept reverse relationships. I'd rather not have to go restructuring my models to make this work... is there anything I can do to make the inlines work with my model as-is?

I fixed that error by making reverse side inline, not from Profile to User but from overridden User to Profile:
class ProfileInline(admin.StackedInline):
model = Profile
class IspUserAdmin(UserAdmin):
list_display = ('username', 'first_name', 'last_name', 'email', 'is_staff', 'is_superuser', 'is_active')
list_filter = ('date_joined', 'last_login', 'is_staff', 'is_superuser', 'is_active',)
inlines = (ProfileInline,)
admin.site.unregister(User)
admin.site.register(User, IspUserAdmin)
Then I also tweaked Profile admin (removed Add action and changed some field links to custom ones).

There's a django module on github that will do this for you, without you having to reverse the relationships: django_reverse_admin.
Once installed, your admin would look like:
# admin.py
from django_reverse_admin import ReverseModelAdmin
class SpecializedProfileAdmin(ReverseModelAdmin):
model = SpecializedProfile
inline_reverse = ['profile']
inline_type = 'tabular' # could also be 'stacked'
admin.site.register(SpecializedProfile, SpecializedProfileAdmin)
Unfortunately, I don't think it can do nested inlines (Django can't either), so that would only solve part of your problem. I know you didn't want to change your database structure, but SpecializedProfile really seems more like a subclass of UserProfile. If you rewrote your model like so:
class SpecializedProfile(UserProfile):
# More fields...
Then you could have the admin like this:
# admin.py
from django_reverse_admin import ReverseModelAdmin
class UserProfileAdmin(ReverseModelAdmin):
model = UserProfile
inline_reverse = ['user_auth']
inline_type = 'tabular'
class SpecializedProfileAdmin(ReverseModelAdmin):
model = SpecializedProfile
inline_reverse = ['user_auth']
inline_type = 'tabular'
admin.site.register(SpecializedProfile, SpecializedProfileAdmin)
admin.site.register(UserProfile, UserProfileAdmin)
This way, you can view everything inline for both UserProfile and SpecializedProfile.

Inline in Django admin: has no ForeignKey

I have two Django models:
class Author(models.Model):
user_email = models.CharField(max_length=100, blank=True)
display_name = models.CharField(max_length=250)
class Photo(models.Model):
author = models.ForeignKey(Author)
image = ThumbnailImageField(upload_to='photos')
To get inline photos, I have in admin.py:
class PhotoInline(admin.StackedInline):
model = Author
class AuthorAdmin(admin.ModelAdmin):
list_display = ('display_name','user_email')
inlines = [PhotoInline]
I get an error: Exception at /admin/metainf/author/11/
<class 'metainf.models.Author'> has no ForeignKey to <class 'metainf.models.Author'>
Why?

The inline model should be having a ForeignKey to the parent model. To get Photo as inline in Author your models code is fine. But your admin code should be as follows:
class PhotoInline(admin.StackedInline):
model = Photo
class AuthorAdmin(admin.ModelAdmin):
list_display = ('display_name','user_email')
inlines = [PhotoInline]
Read more info here.

That's because Author doesn't have a foreign key to photo. I think you need to switch the model for the inline like this:
class PhotoInline(admin.StackedInline):
model = Photo
class AuthorAdmin(admin.ModelAdmin):
list_display = ('display_name','user_email')
inlines = [PhotoInline]

Maybe you need to install django-nested-admin library, and later try with NestedStackedInline.
django-nested-admin

Django Admin: Ordering of ForeignKey and ManyToManyField relations referencing User

I have an application that makes use of Django's UserProfile to extend the built-in Django User model. Looks a bit like:
class UserProfile(models.Model):
user = models.ForeignKey(User, unique=True)
# Local Stuff
image_url_s = models.CharField(max_length=128, blank=True)
image_url_m = models.CharField(max_length=128, blank=True)
# Admin
class Admin: pass
I have added a new class to my model:
class Team(models.Model):
name = models.CharField(max_length=128)
manager = models.ForeignKey(User, related_name='manager')
members = models.ManyToManyField(User, blank=True)
And it is registered into the Admin:
class TeamAdmin(admin.ModelAdmin):
list_display = ('name', 'manager')
admin.site.register(Team, TeamAdmin)
Alas, in the admin inteface, when I go to select a manager from the drop-down box, or set team members via the multi-select field, they are ordered by the User numeric ID. For the life of me, I can not figure out how to get these sorted.
I have a similar class with:
class Meta:
ordering = ['name']
That works great! But I don't "own" the User class, and when I try this trick in UserAdmin:
class Meta:
ordering = ['username']
I get:
django.core.management.base.CommandError: One or more models did not validate:
events.userprofile: "ordering" refers to "username", a field that doesn't exist.
user.username doesn't work either. I could specify, like image_url_s if I wanted to . . . how can I tell the admin to sort my lists of users by username? Thanks!

This
class Meta:
ordering = ['username']
should be
ordering = ['user__username']
if it's in your UserProfile admin class. That'll stop the exception, but I don't think it helps you.
Ordering the User model as you describe is quite tricky, but see http://code.djangoproject.com/ticket/6089#comment:8 for a solution.

One way would be to define a custom form to use for your Team model in the admin, and override the manager field to use a queryset with the correct ordering:
from django import forms
class TeamForm(forms.ModelForm):
manager = forms.ModelChoiceField(queryset=User.objects.order_by('username'))
class Meta:
model = Team
class TeamAdmin(admin.ModelAdmin):
list_display = ('name', 'manager')
form = TeamForm

This might be dangerous for some reason, but this can be done in one line in your project's models.py file:
User._meta.ordering=["username"]

For me, the only working solution was to use Proxy Model. As stated in the documentation, you can create own proxy models for even built-in models and customize anything like in regular models:
class OrderedUser(User):
class Meta:
proxy = True
ordering = ["username"]
def __str__(self):
return '%s %s' % (self.first_name, self.last_name)
After that, in your model just change Foreign Key to:
user = models.OneToOneField(OrderedUser, unique=True)
or even more suitable
user = models.OneToOneField(OrderedUser, unique = True, parent_link = True)