Django link multiple table - django

Question

I have four models as follows:
class deals_view(models.Model):
deal = models.ForeignKey(dealsModel, on_delete=models.CASCADE, related_name='deal_view')
client = models.ForeignKey(client_profileModel, on_delete=models.CASCADE)
client_ip = models.GenericIPAddressField(protocol='both')
date_added = models.DateField(auto_now_add=True)
class client_profile(models.Model):
GENDER_NAME = (
('M', 'Male'),
('F', 'Female'),
('O', 'Others')
)
user = models.ForeignKey(User, unique=True, on_delete=models.CASCADE)
gender = models.CharField(max_length=1, choices=GENDER_NAME, null=True)
address = models.CharField(max_length=100, null=True)
dob = models.DateField(null=True)
class deals(models.Model):
GENDER_NAME = (
('M', 'Male'),
('F', 'Female'),
('O', 'Others'),
('A', 'All'),
)
AGE_RANGE = (
('A1', '18-25'),
('A2', '25-40'),
('A3', '40-55'),
('A4', '55-100'),
('A5', '18-100'),
('AL', '13-100'),
('T1', '13-18')
)
store = models.ForeignKey(storesModel, on_delete=models.CASCADE, related_name='deals_store')
title = models.CharField(max_length=30)
description = models.CharField(max_length=160)
price = models.DecimalField(max_digits=6, decimal_places=2)
category = models.ForeignKey(categoriesModel, on_delete=models.PROTECT)
targeted_gender = models.CharField(max_length=1, choices=GENDER_NAME)
targeted_age = models.CharField(max_length=2, choices=AGE_RANGE)
is_active = models.BooleanField(default=False)
created_date = models.DateField(auto_now_add=True)
expiry_date = models.DateField(default=(dt.now() + td(days=30)))
class stores(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE)
name = models.CharField(max_length=50, unique=True)
about = models.CharField(max_length=300)
company_name = models.CharField(max_length=100)
I want to list all deals for the current month and its corresponding number of views per gender.
so far I've tried the following; i can get all the info but it seems i have multiple hits of the database:
self.storeObj = storesModel.objects.prefetch_related('deals_store').get(id=storeid)
self.deals_store = self.storeObj.deals_store
segmentedInfo = self.deals_store.all().prefetch_related('deal_view').filter(deal_view__date_added__range=((datetime.today() - timedelta(days=30)), datetime.now())).distinct()
for seg in segmentedInfo:
for x in seg.deal_view.select_related('client').distinct():
print(x.client.gender)
Is there any way i can optimise my queries to get the number of views per gender for a deal of a specific store?

Answer 1

Yes, we can do some filtering in the related client_profile model, and then use a .annotate(..) to count the number of distinct ids.
from django.db.models import Count
client_profile.objects.filter(
deals_view__deal__store_id=storeid,
deals_view__date_added__range=(datetime.today()-timedelta(days=30), datetime.now())
).values('gender').annotate(
n=Count('id', distinct=True)
).order_by('gender')
This will result in a QuerySet that contains dictionaries with the gender, and the number of client_profiles, like:
<QuerySet [
{'gender': 'M', 'n': 1425},
{'gender': 'M', 'n': 1302},
{'gender': 'O', 'n': 173}
]>
If there are no client_profiles with a given gender that have seen the deal, then it is not part of the QuerySet.