Inside Django class-base CreateView, how to init intermediate model - django-views

Question

I have three models, PiItem is the interface of Pi and Items models by "through".
Right now I want to create a new Items instance with new Pi instance and new PiItem instance inside Django CreatedView class.
Somehow I keep getting error message
*
*****MultipleObjectsReturned at /product/ get() returned more than one PiItem*****
*
Any help will be highly appreciated
THANKS
here are the models
class Pi(models.Model):
company = models.ForeignKey(CompanyProfile, related_name='pi', null=True)
contact = models.ForeignKey(Contact, null=True)
def __unicode__(self):
#return u'%s, %s' %(self.company.companyprofile_name, self.reference_id)
return u'%s' %(self.company.companyprofile_name)
class Items(models.Model):
product_id = models.CharField("Product ID",max_length=50, blank=False, null=True, unique=True)
in_pi = models.ManyToManyField(Pi, through='PiItem', blank=True)
def __unicode__(self):
return self.product_id
class PiItem(models.Model):
item_name= models.ForeignKey(Items)
pi = models.ForeignKey(Pi)
def __unicode__(self):
return self.pi.reference_id
and here is my view.py
from django.views.generic.edit import CreateView
from pi.models import Items, PiItem, Pi
from django.shortcuts import get_object_or_404
class AddItemView(CreateView):
context_object_name = 'Product_list'
model = Items
template_name = "product.html"
fields = "__all__"
def get_initial(self):
in_pi = get_object_or_404(PiItem)
return {
'in_pi':in_pi
}
and here is the template
{% extends 'base.html' %}
{% load crispy_forms_tags %}
{% block pi %}
<form action="" method="post">{% csrf_token %}
{{ form|crispy }}
{{ form.get_form_class() }}
<input type="submit" value="Create" />
</form>

Answer 1

Problem most likely is here:
in_pi = get_object_or_404(PiItem)
You need to filter the PiItem object by passing additional arguments, such as foreigk key to each related model, like:
in_pi = get_object_or_404(PiItem, item_name=something1, pi=something2)