How to get IntegerField from ForegienKey for objects model - django

Question

I have a profile, and in this profile I want to display bookmarks for all messages (this is my IntegerField). In other words, how many people have bookmarked a particular author's posts.
models.py
class Post(models.Model):
slug = models.SlugField(unique=True)
title = models.CharField(max_length=255, db_index=True)
author = models.ForeignKey(
"users.CustomUser", on_delete=models.SET_NULL, null=True, db_index=True
)
bookmarkscount = models.IntegerField(null=True, blank=True, default=0)
class Profile(models.Model):
user = models.OneToOneField(get_user_model(), on_delete=models.CASCADE)
This is my try in template but it does not work
<p>Bookmark</p>
<p>{{posts.bookmarkscount}}</p>
But work only if I use "for"
{% for post in posts %}
<p>{{ post.bookmarkscount}}</p>
{% endfor %}
views.py
class ProfileDetailView(DetailView):
model = Profile
template_name = "users/profile/profile.html"
def get_context_data(self, **kwargs):
try:
context["posts"] = Post.objects.filter(
author=self.object.user.is_authenticated
)
except Post.DoesNotExist:
context["posts"] = None

Answer 1

posts is a QuerySet type, a representation of the query to be sent to the DB. More like a list on steroids rather than a single instance of Post. This is a crucial concept you need to understand before coding anything in Django. (Docs here)
In order to get a sum of all the bookmarkscount values from all posts of a user, you need to use aggregation. (Docs here)
from django.db.models import Sum
posts.aggregate(Sum('bookmarkscount'))
# returns i.e.: {'bookmarkscount': 234}