Count foreign objects for model

Question

I have following models (simplified) in Django app:

class Company(BaseModel):
    user = models.OneToOneField(User)
    title = models.CharField(max_length=128)

class Event(BaseModel):
    company= models.ForeignKey(Company)
    description = models.TextField(verbose_name="Description", blank=True,null=True,max_length=200,default="")

in one of my views, I want to count Event objects for company "owned" by logged user. to access company object I use something like request.user.company

How can I count all Event objects related to single company?

EDIT:

I think I asked wrong question. What I want to do: I select single event object:

event = Event.objects.get(uuid=event_uuid)

and now I want to get number of Event but within single company, not global ID.

write data sample and expected result.

dani herrera
– dani herrera

2013-06-01 13:32:21 +00:00
Commented Jun 1, 2013 at 13:32 — dani herrera
– dani herrera, Commented Jun 1, 2013 at 13:32

andrea.ge · Accepted Answer · 2013-06-01 15:13:53Z

2

I found hard to understand your question, do you want to count Event associated to a given Company?

c = Company.objects.get(...)
event_n = Event.objects.filter(company=c).count()

or

n = 2
event_n = Event.objects.filter(company__pk=n).count()

or

u = User.objects.get(...)
event_n = Event.objects.filter(company__user=u).count()

Do you want to collect one (some) company (companies) with the number of Event associated?

from django.db.models import Count
company = Company.objects.filter(pk=n).annotate(event_n=Count('event')).get()
print company.event_n

or

companies = Company.objects.filter(...).annotate(event_n=Count('event'))
for c in companies:
    print c.event_n

If you already have an event and you want the number of events associated to its company you can try

e = Event.objects.get(...)
event_n = Event.objects.filter(company=e.company).count()

or

n = 3
e = Event.objects.filter(pk=n).annotate(event_n=Count('company__event')).get()
print e.event_n

edited Jun 1, 2013 at 15:13

answered Jun 1, 2013 at 14:57

andrea.ge

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2 Comments

dease Over a year ago

Sorry for being unclear. So, I have several Company objects. Each of them has multiple events. When I show single event, I want to display number of this single event (not count) within parent company. Example: I have Event1 assigned to Company1 Event2 assigned to Company2 Event3 assigned to Company1 then, when displaying Event3 I want to show "ID:2"

andrea.ge Over a year ago

An example id/primary key of your Event. Instead of pk=3 you can use uuid=event_uuid or whatever you like.

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