CODEWITHSUNDEEP
pythondjangomodeldjango-rest-framework
Sadar Ali
Sadar Ali

Reputation: 153

Django Model Query

I have the following 2 models:

class User(models.Model):
    user_id = models.IntegerField(null=True)
    name = models.CharField(max_length=50)

class Blog(models.Model):
    id = models.IntegerField(primary_key=True)
    user = models.ForeignKey(User, null=True)
    timestamp = models.DateTimeField()

How can I write a Django model query to get a list of objects which has the following formation - 

[(user_object, number of blog posts of this user), ...]

This list is supposed to be in descending order. Basically, I want to obtain information about how many blog posts a user has written.

Incase, 2 users have the same number of blog posts, I want them to be sorted based on the latest timestamp of the blogpost created by them.

So, far I've tried the following and remained unsuccessful in my approaches.

    user = User.objects.all()
    serializer = UserSerializer(user, many=True)
    user = list(serializer.data)
    user_ranks = [(key, len(list(group))) for key, group in groupby(user)]
    user_ranks = sorted(user_ranks, key=lambda x: x[1], reverse=True)

I do not know how to plug in the timestamp comparison into the above mentioned code. Also, is there a better way of achieving this?

P.S: Number of entries in User is same as number of entries in Blog

Upvotes: 0

Views: 80

Answers (1)

DisneylandSC
DisneylandSC

Reputation: 966

if you set

user = models.ForeignKey(User, null=True, related_name='bloguser')

You can use 

from django.db.models import Count
some_query = User.objects.filter( ... ).annotate( foobar = count('bloguser') )

to attach the number of blogs, which you can then access in your template via some_query.foobar.

for the time stamp

some_query = User.objects.filter( ... ).annotate( foobar = count('bloguser') ).annotate( foomax = Max('bloguser__timestamp') )

Upvotes: 1

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