class MyModel(models.Model):
    email = models.EmailField(unique=True)

class MyModelForm(forms.ModelForm):
    class Meta:
        model = MyModel

def my_model_view(request, model_id):
    obj = get_object_or_404(MyModel, pk=model_id)
    if request.method == 'POST':
        form = MyModelForm(request.POST, instance=obj)
        if form.is_valid():
            obj = form.save()
    else:
        form = MyModelForm(instance=obj)
    render_to_response(
        'my_model_template.html', {'form': form},
        context_instance=RequestContext(request)
    )