Update another model's object after a form submit - django

Question

I am attempting to update another model's object after a form submit. I would like the single object, already in existence within the Savings model, updated to reflect the most recent Entry submission.
Process:
Once the Entry form is filled out and submitted, I need the Savings object, which contains the "total" fields, to be updated.
The Savings fields take data from the Entry form, sums it, and posts it to its corresponding fields. For example, Savings.total_spent_euros sums Entry.euros_sums, and Savings.total_spent_dollars sums Entry.dollars_sum. That logic is not the issue. The problem I have is I currently have to open the Savings object in admin and save it every time I want the object to include the most recent entries. I would like to automate that.
models.py
class Entry(models.Model):
date = models.DateField(blank=True, null=True,)
euros = models.CharField(max_length=500, blank=True, null=True)
comments = models.CharField(max_length=900, blank=True, null=True)
euros_sum = models.DecimalField(max_digits=6, decimal_places=2, blank=True, null=True)
xrate = models.DecimalField(max_digits=6, decimal_places=2, blank=True, null=True)
dollars_sum = models.DecimalField(max_digits=6, decimal_places=2, blank=True, null=True)
daily_savings_dollars = models.DecimalField(max_digits=6, decimal_places=2, blank=True, null=True)
daily_savings_display = models.DecimalField(max_digits=6, decimal_places=2, blank=True, null=True)
def get_absolute_url(self):
return reverse('argent:detail', kwargs={'pk': self.pk})
class Savings(models.Model):
total_spent_euros = models.DecimalField(max_digits=6, decimal_places=2, blank=True, null=True)
total_spent_dollars = models.DecimalField(max_digits=6, decimal_places=2, blank=True, null=True)
total_savings = models.DecimalField(max_digits=6, decimal_places=2, blank=True, null=True)
total_savings_display = models.DecimalField(max_digits=6, decimal_places=2, blank=True, null=True)
Am I assuming correctly that my command must be entered within these two views? (I could be wrong):
views.py
class EntryCreate(CreateView):
form_class = EntryForm
template_name = 'argent/entry_form.html'
def form_valid(self, form):
Savings.objects.update(id=1)
return super(EntryCreate, self).form_valid(form)
class EntryUpdate(UpdateView):
model = Entry
form_class = EntryForm
template_name = 'argent/entry_form.html'
def form_valid(self, form):
Savings.objects.update(id=1)
return super(EntryUpdate, self).form_valid(form)
However, whenever I use Savings.objects.update(id=1) or Savings.objects.filter(id=1).update(), nothing happens. What am I overlooking here?
Thanks in advance for your help!
EDIT: Added a bit more detail.

Answer 1

SOLUTION
With the help of nik-m we finally came up with a solution. Here is my updated views.py. Not only did I have to use the .update solution, but I had to include all of the logic that is otherwise housed within my forms.py.
views.py
class EntryCreate(CreateView):
form_class = EntryForm
template_name = 'argent/entry_form.html'
def form_valid(self, form):
if form.save(self):
# total_euros_spent
sum_euros = Entry.objects.aggregate(s=Sum('euros_sum')).get('s')
sum_euros_f = "{0:.2f}".format(sum_euros)
# total_dollars_spent
sum_dollars = Entry.objects.aggregate(s=Sum('dollars_sum')).get('s')
sum_dollars_f = "{0:.2f}".format(sum_dollars)
# total_sum
sum_savings = Entry.objects.aggregate(s=Sum('daily_savings_dollars')).get('s')
sum_format = "{0:.2f}".format(sum_savings)
# total_sum_format
sum_abs_savings = Entry.objects.aggregate(s=Sum('daily_savings_dollars')).get('s')
absolute = abs(sum_abs_savings)
sum_abs = "{0:.2f}".format(absolute)
Savings.objects.filter(id=1).update(total_savings=sum_format, total_savings_display=sum_abs,
total_dollars_spent=sum_dollars_f, total_euros_spent=sum_euros_f)
return super(EntryCreate, self).form_valid(form)
else:
return self