I have a standard many-to-one relationship set up. There are a bunch of fields, but for our purposes here, the relevant model is:
class Class(models.Model):
name = models.CharField(max_length=128)
class Student(models.Model):
class = models.ForeignKey(Class)
name = models.CharField(max_length=128)
address = models.CharField(max_length=128)
# ...etc
I created an admin, and it works great. it even automatically has the ability for me to set the Class when I am editing a Student. However, when I go to create/edit a Class, all I get is an input box for the name.
Is there a way to add a box/field where Students can be added as members of Class from the Class admin page? I can make a form inline, but that is to create new Students. I already have all my Students created and am just looking for a quick method to add multiple existing Students to different Class'.
To handle One-To-Many relationships in Django you need to use ForeignKey . The current structure in your example allows each Dude to have one number, and each number to belong to multiple Dudes (same with Business).
django-inline-actions provides a handy templatetag render_inline_action_fields , which adds these information as hidden fields to a form. As the action does not know that an intermediate form is used, we have to include some special handling.
There is! You want InlineModelAdmin
(see InlineModelAdmin documentation here)
Sample code in brief:
class StudentAdminInline(admin.TabularInline):
model = Student
class ClassAdmin(admin.ModelAdmin):
inlines = (StudentAdminInline, )
admin.site.register(Class, ClassAdmin)
Here is "custom form" solution as Luke Sneeringer suggested. Anyway, I'm suprised by absence of out-of-the-box Django solution to this (rather natural and probably common) problem. Am I missing something?
from django import forms
from django.db import models
from django.contrib import admin
class Foo(models.Model):
pass
class Bar(models.Model):
foo = models.ForeignKey(Foo)
class FooForm(forms.ModelForm):
class Meta:
model = Foo
bars = forms.ModelMultipleChoiceField(queryset=Bar.objects.all())
def __init__(self, *args, **kwargs):
super(FooForm, self).__init__(*args, **kwargs)
if self.instance:
self.fields['bars'].initial = self.instance.bar_set.all()
def save(self, *args, **kwargs):
# FIXME: 'commit' argument is not handled
# TODO: Wrap reassignments into transaction
# NOTE: Previously assigned Foos are silently reset
instance = super(FooForm, self).save(commit=False)
self.fields['bars'].initial.update(foo=None)
self.cleaned_data['bars'].update(foo=instance)
return instance
class FooAdmin(admin.ModelAdmin):
form = FooForm
Probably, this will help:
I used the described approach, but changed methods save
and save_m2m
in the following way:
from django import forms
from django.db import models
from django.contrib import admin
class Foo(models.Model):
pass
class Bar(models.Model):
foo = models.ForeignKey(Foo)
class FooForm(forms.ModelForm):
class Meta:
model = Foo
bars = forms.ModelMultipleChoiceField(queryset=Bar.objects.all())
def __init__(self, *args, **kwargs):
super(FooForm, self).__init__(*args, **kwargs)
if self.instance:
self.fields['bars'].initial = self.instance.bar_set.all()
def save_m2m(self):
pass
def save(self, *args, **kwargs):
self.fields['bars'].initial.update(foo=None)
foo_instance = Foo()
foo_instance.pk = self.instance.pk
# Copy all other fields.
# ... #
foo_instance.save()
self.cleaned_data['bars'].update(foo=instance)
return instance
class FooAdmin(admin.ModelAdmin):
form = FooForm
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