Django model query with Foreign key and get logged in user - django

Question

Hi I am trying to add "fields" to my django projects that would be calculated based on query..
Basically I have 2 models one is a user which is an extension of Abstract user
class CustomUser(AbstractUser):
pass
and my main model is Project
class Project(models.Model):
id = models.AutoField(primary_key=True)
user = models.ForeignKey(CustomUser, on_delete=models.PROTECT, editable=False)
name = models.CharField(max_length=20, editable=False)
total = models.DecimalField(max_digits=6, decimal_places=2, editable=False)
created = models.DateTimeField(auto_now_add=True, editable=False, null=False, blank=False)
this_month = datetime.datetime.now().month
allprojectsthismonth = Project.objects.filter(created__month=this_month)
def __str__(self):
return self.name
I create Project objects via a web form using this view:
def homepage(request):
if request.method == "POST":
project = Project()
name = request.POST.get('name')
total = request.POST.get('total')
created = datetime.datetime.now()
user = request.user
project.user = user
project.name = name
project.total = total
project.created = created
project.save()
#return HttpResponse(reverse("homepage.views.homepage"))
return render(request, 'homepage.html')
else:
return render(request, 'homepage.html')
What I need now is to have a queryset that gets me the combination of the total of a given user Project object so that I can make calculations on it, how would I go about doing that?
ideally I would get the logged in user and I could add to my view the sum of all Project.object.total with user = currently logged in.
Thanks
EDIT: Would this work?
class Project(models.Model):
id = models.AutoField(primary_key=True)
user = models.ForeignKey(CustomUser, on_delete=models.PROTECT, editable=False)
name = models.CharField(max_length=20, editable=False)
total = models.DecimalField(max_digits=6, decimal_places=2, editable=False)
created = models.DateTimeField(auto_now_add=True, editable=False, null=False, blank=False)
this_month = datetime.datetime.now().month
projectsthismonth = self.objects.filter(created__month=this_month)
def monthlyTotal(self,request):
projectsthismonth.objects.filter(
user=request.user
).aggregate(
sum_total=Sum('total')
)['sum_total']
I seem to be missing something however.

Answer 1

You can obtain the queryset of the Projects where the user is the logged in user with:
Project.objects.filter(user=request.user)
If you want to make simple aggregates (like sum, count, etc.), you better use .aggregate(…) [Django-doc] since then the calculations are done at the database level. For example:
from django.db.models import Sum
Project.objects.filter(
user=request.user
).aggregate(
sum_total=Sum('total')
)['sum_total']
will retrieve the sum of the totals of the Projects with user=request.user, this will be None if there are no projects related to the user at all.
from django.utils.timezone import now
class Project(models.Model):
id = models.AutoField(primary_key=True)
user = models.ForeignKey(CustomUser, on_delete=models.PROTECT, editable=False)
name = models.CharField(max_length=20, editable=False)
total = models.DecimalField(max_digits=6, decimal_places=2, editable=False)
created = models.DateTimeField(auto_now_add=True)
def monthlyTotal(self,user):
this_month = now().month
return Project.objects.filter(
created__month=this_month,
user=user
).aggregate(
sum_total=Sum('total')
)['sum_total']
Note: You can limit views to a view to authenticated users with the
#login_required decorator [Django-doc].