django admin - select reverse foreign key relationships (not create, I want to add available)

Question

Lets say I have a model School and another model Student.

class Student(models.Model):
   school = models.ForeignKey(School)
   name =          


        

Answer 1

class SchoolAdminForm(forms.ModelForm):
    students = forms.ModelMultipleChoiceField(
        queryset=Student.objects.all(),
        widget=FilteredSelectMultiple(verbose_name='students', is_stacked=False))

    class Meta:
        model = School
        fields = ['your_school_fields_go_here']

    def __init__(self, *args, **kwargs):
        super(SchoolAdminForm, self).__init__(*args, **kwargs)
        if self.instance:
            # fill initial related values
            self.fields['students'].initial = self.instance.student_set.all()

class SchoolAdmin(admin.ModelAdmin):
   form = SchoolAdminForm

   def save_model(self, request, obj, form, change):
       original_students = obj.student_set.all()
       new_students = form.cleaned_data['students']
       remove_qs = original_students.exclude(id__in=new_students.values('id'))
       add_qs = new_students.exclude(id__in=original_students.values('id'))
       for item in remove_qs:
           obj.student_set.remove(item)
       for item in add_qs:
           obj.student_set.add(item)
       obj.save()