Hi Patrick,
you can do like this:
def total(self):
return ContractItem.objects.filter(contract__subbudget__budge__in=
self.budget_set.all()).aggregate(Sum('total'))['total__sum']
try like this..!
On Wed, Feb 1, 2017 at 7:14 PM, Patrick Joy <[email protected]> wrote:
> Hi all,
>
> Would appreciate some advice on this, I'm having trouble working out the
> best way to aggregate across multiple foreign key relationships. I have
> come up with the solution below however I'm not sure if this is the correct
> way to handle this situation. Any advice would be appreciated.
>
> Thanks
>
>
> As an example I have a model structure that is 5 levels deep with foreign
> keys between each level, cost information is recorded at the lowest level
> (ContractItem)
>
> --- Project
> |--- Budget
> |--- SubBudget
> |--- Contract
> |--- ContractItem - $100
>
> If I want to aggregate the total cost up to the top project level I do it
> in multiple steps like this:
>
> class Project(models.Model):
> name = models.CharField(max_length=50)
>
> def total(self):
> subbudgets = SubBudget.objects.filter(budget__in=self.budget_set.
> all())
> contracts = Contract.objects.filter(subbudget__in=subbudgets)
> return ContractItem.objects.filter(contract__in=contracts).
> aggregate(Sum('total'))['total__sum']
>
>
> Is there a better way of doing this?
>
>
> Full working code:
>
> class Project(models.Model):
> name = models.CharField(max_length=50)
>
> def total(self):
> subbudgets = SubBudget.objects.filter(budget__in=self.budget_set.
> all())
> contracts = Contract.objects.filter(subbudget__in=subbudgets)
> return ContractItem.objects.filter(contract__in=contracts).
> aggregate(Sum('total'))['total__sum']
>
> def __str__(self):
> return self.name
>
> class Budget(models.Model):
> project = models.ForeignKey(Project)
> name = models.CharField(max_length=50)
>
> def __str__(self):
> return self.name
>
> def total(self):
> contracts = Contract.objects.filter(subbudget__in=self.subbudget_
> set.all())
> return ContractItem.objects.filter(contract__in=contracts).
> aggregate(Sum('total'))['total__sum']
>
>
> class SubBudget(models.Model):
> budget = models.ForeignKey(Budget)
> name = models.CharField(max_length=50)
>
> def __str__(self):
> return self.name
>
> def total(self):
> return ContractItem.objects.filter(contract__in=self.contract_
> set.all()).aggregate(Sum('total'))['total__sum']
>
>
> class Contract(models.Model):
> subbudget = models.ForeignKey(SubBudget)
> name = models.CharField(max_length=50)
>
> def __str__(self):
> return self.name
>
> def total(self):
> return self.contractitem_set.aggregate(Sum('total'))['total__sum']
>
> class ContractItem(models.Model):
> contract = models.ForeignKey(Contract)
> total = models.DecimalField(default=0.00, decimal_places=2,
> max_digits=12)
> name = models.CharField(max_length=50)
>
> def __str__(self):
> return self.name
>
> --
> You received this message because you are subscribed to the Google Groups
> "Django users" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to [email protected].
> To post to this group, send email to [email protected].
> Visit this group at https://groups.google.com/group/django-users.
> To view this discussion on the web visit https://groups.google.com/d/
> msgid/django-users/f1a3bfb7-f342-423d-8790-fc0d5bbcf151%40googlegroups.com
> <https://groups.google.com/d/msgid/django-users/f1a3bfb7-f342-423d-8790-fc0d5bbcf151%40googlegroups.com?utm_medium=email&utm_source=footer>
> .
> For more options, visit https://groups.google.com/d/optout.
>
--
You received this message because you are subscribed to the Google Groups
"Django users" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at https://groups.google.com/group/django-users.
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-users/CAGGVXBNTWdS1ESfBWF2hQVqz2zoPYmURCkWY8j8b-wfiVzBQnw%40mail.gmail.com.
For more options, visit https://groups.google.com/d/optout.
