Django ModelForm - django

Question

I am trying to create a simple CRUD with ModelForm. It works fine except that every time I edit, saving creates a new instance of the data. So i edit and get an extra row in DB instead of an updated one. I am at a loss as to how it knows to save an existing charity as it does not store the PK (id) as a hidden field in the form. That is how I always did it before trying to use the 'fabulous' ModelForm!
It's driving me nuts, I have read everything and as far as I can tell I am doing everything right.
Here is my code..
Model:
from django.db import models
from django.conf import settings
COUNTRY_CHOICES = settings.COUNTRIES
class Charities(models.Model):
charity_name = models.CharField(max_length=100)
country = models.CharField(max_length=4, choices=COUNTRY_CHOICES)
registration_number = models.CharField(max_length=100)
address1 = models.CharField(max_length=100)
address2 = models.CharField(max_length=100)
city = models.CharField(max_length=30)
zip = models.CharField(max_length=10)
phone = models.CharField(max_length=20)
email = models.EmailField()
charity_logo_image = models.CharField(max_length=100)
charity_banner_image = models.CharField(max_length=100)
charity_accepted = models.IntegerField()
def __str__(self):
return self.charity_name
def __unicode__(self):
self.charity_name
View:
def list(request):
charities = Charities.objects.all()
return render_to_response('charities_charity_list.html', {'charities': charities})
def add(request):
return add_or_edit(request)
def edit(request, charity_id):
return add_or_edit(request, charity_id)
def add_or_edit(request, charity_id=None):
print "ID = " + str(charity_id)
form = CharityForm(request.POST or None,
instance=charity_id and Charities.objects.get(pk=charity_id))
# Save new/edited student
if request.method == 'POST' and form.is_valid():
print form
form.save()
return HttpResponseRedirect('/charities/list/')
return render_to_response('charities_charity_edit.html', {'form': form})
Form:
class CharityForm(ModelForm):
class Meta:
model = Charities
Template:
{% extends "base.html" %}
{% block title %}Charities Add{% endblock %}
{% block content %}
<form method="post" action="/charities/add/" id="save"><table cellpadding="0">{{ form.as_table}}</table><input type="submit" value="Save"></form>
{% endblock %}

Answer 1

It doesn`t work because your template is always POSTing to the view that adds a new Charity. When you manually type a URL like /charities/edit/5, it creates the ModelForm with the right initial data, but then POSTs to /charities/add, thus creating a new instance. You need to POST to /charities/edit/5, for example. Take a look at the url template tag.
I suggest you use 2 templates, one for adding, another for editing. I know it may not be very DRY, but I believe it's clearer this way.
Add template:
{% extends "base.html" %}
{% block title %}Charities Add{% endblock %}
{% block content %}
<form method="post" action="{% url charities_app.views.add %}"><table cellpadding="0">{{ form.as_table}}</table><input type="submit" value="Save"></form>
{% endblock %}
Edit template:
{% extends "base.html" %}
{% block title %}Edit Charity{% endblock %}
{% block content %}
<form method="post" action="{% url charities_app.views.edit charity.id %}"><table cellpadding="0">{{ form.as_table}}</table><input type="submit" value="Save"></form>
{% endblock %}
You may also want to check the create_object and update_object generic views, they are very useful in simple cases like yours.