Styjun

I am trying to create a ratings app for a news aggregation site, but I think either my implementation of the apps or the foreignkey queries from ratings to articles is wrong. I keep getting

raise AppRegistryNotReady("Models aren't loaded yet.")

django.core.exceptions.AppRegistryNotReady: Models aren't loaded yet.

when migrating. The idea is that each user's individual rating of an article is handled by ArticleRating, and then each article would have an average score handled by OverallArticleRating

I think the issue goes down to one of 3 things:
1. the user ratings should be implemented as a model in the articles app, then referenced by the OverallRatings model.
2. my foreign key queryset syntax is incorrect. I have tried using article.articlerating_set for the queryset of ArticleRating objects, but that only returns attribute not defined.
3. I need to reference the article object associated with each rating object differently.

from django.db import models
from users.models import User
from Articles.models import Article





class AbstractRating(models.Model):
 score = models.IntegerField()



 def __str__(self):
 return str(self.score)

 class Meta:
 abstract = True
 ordering= ['-score']

class ArticleRating(AbstractRating):
 article = models.ForeignKey(Article, on_delete=models.CASCADE)
 rater = models.ForeignKey(User, on_delete=models.CASCADE)

class OverallArticleRating(AbstractRating):
 article = models.ForeignKey(Article, on_delete=models.CASCADE)
 def getArticleAverageScore(art):
 sumUserScore = 0
 averageUserScore = 0
 ratingSet = ArticleRating.objects.filter(article=art)
 if len(ratingSet) > 0:
 for userRating in userRatingSet:
 sumUserScore += userRating.score
 averageUserScore = sumUserScore/(ArticleRating.objects.filter( article=art).count())
 return averageUserScore
 else: 
 return 0

 score = getArticleAverageScore(article)

The problem is the last line, where you're calling getArticleAverageScore at class level That's doesn't make any sense; you need to call it with an instance of the model, but as it is it's being called at definition time before there are any instances at all.

If you need a score attribute that always reflects the average score, then use a property:

@property
def score(self):
 sumUserScore = 0
 sumUserScore = 0
 averageUserScore = 0
 ratingSet = ArticleRating.objects.filter(article=set)
 ...

However, also note that your method is really inefficient. You should use aggregation instead.