1

Suppose, I am making a movie rating app. A logged-in user should be able to rate the movie with stars (in the range 1 to 5).

I want to quickly access all the rater's name along with their rating. If a user rates the movie again, the rating should be updated. At the same time, if a user decides to withdraw his rating i.e. provide zero rating, I would like to remove the entry from the field.

I believe dictionary would be the best choice to achieve the same. However, I am open for suggestions.

I also want a user to see all the movies the he/she has rated along with the rating.

Vishal Kumar Mishra
  • 29
  • 1
  • 6

4 Answers4

2

You should create an ForeignKey field between the user model and the voting model. To only allow a single vote, per user; per movie, you might want to create a unique key constraint, on the voting model, over the userid and the movieid.

The vote should then contain a relation to the movie and a rating. If a user withdraws his vote you remove it from database.

Using a dictionary will lead to problems for you as you will have multiple movies.

To increase the speed and performance counting the votes you might want to take a look at caching and simply cache the number of votes and update the number every time a vote was added/withdrawn by a user on the specific movie.

Iwan1993
  • 1,669
  • 2
  • 17
  • 25
0

You can use: update_or_create() method with django ORM. https://docs.djangoproject.com/en/1.10/ref/models/querysets/#update-or-create

Marcin Świerczyna
  • 112
  • 4
0

If the database you are using is Postgres, then you can make use of JSONField

dentemm
  • 6,231
  • 3
  • 31
  • 43
  • I cannot recommend a JSONField, as multiple users might want to vote on a movie at the same time, and the database will have to rewrite the value over and over again, locking the voting for a movie at time. This will be a bottleneck for sure. – Iwan1993 Apr 10 '17 at 11:25
  • @Iwan1993 I think you best use separate models for a user vote and a rating score in that case – dentemm Apr 10 '17 at 11:29
0

Have you checked django-star-ratings, Star ratings for your Django models with a single template tag.

Surajano
  • 2,688
  • 13
  • 25