I've started building an app in Django that will require multi-criteria weighted ratings. My issue is the exact same as this one from a few years ago, which unfortunately did not have any answer.
If anybody out there can give me some hints on how to make multi-criteria weighted ratings in Django, I would love to hear about it! I'm pretty new to the whole Django/Python world and come from a PHP background.
Thanks a lot!
PS: I did not put too much info in this thread, because the problem is already described on the other topic here. It's exactly the same thing.
The easiest solution for the weighted rating would be to add an additional field and populate it automatically in a custom save method on the rating object.
As far as getting the overall average rating goes, you can either calculate it dynamically every time it's needed (easiest/most accurate method) using Django's aggregation queries, or you can try to maintain an average rating field that is updated each time a rating is added/deleted/updated (the more performant method if you're running a read-heavy service). See my answer here for more details on implementing these (using sums rather than averages) and more detail on the tradeoffs.