CODEWITHSUNDEEP
pythondjangosqlite
Luke Acko13
Luke Acko13

Reputation: 61

Storing a list of data in a list django

I am creating an upvoting system where the user upvotes, however to prevent a user from voting more than once I need to store a list of all users who have upvoted the post, I am using sqlite3 database, I would like to know how to go about storing these users in a list in my post model, I have tried several diffrent options but they havent worked.

Database: sqlite3 Python Version: 3.8 Django Version: 3.0.3

current attempt:

models.py:

class Upvote(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    post = models.ForeignKey(Post, on_delete=models.CASCADE)

current code :

def up_vote(request, pk):
    current_user=request.user
    pk=Post.objects.get(pk)


    try:
        post_instance = Post.objects.get(pk) 
        upvote = Upvote(post=post_instance, user=current_user)
    except Upvote.DoesNotExist:
        post_instance = Post.objects.get(pk)
        upvote = Upvote(post=post_instance, user=current_user)
    return redirect(Post(pk))

Upvotes: 0

Views: 54

Answers (2)

Ramtin
Ramtin

Reputation: 3205

You need to have an Upvote model with a foreign key to the Post model. Take this as an example:

class Upvote(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    post = models.ForeignKey(Post, on_delete=models.CASCADE)

Once the user upvotes a post you create a row in the Upvote table. You can check if the user has already upvoted the post by using a try block:

try:
    upvote = Upvote.objects.get(post=some_post, user=some_user)
    # User has upvoted
    # Response accordingly
except Upvote.DoesNotExist:
    upvote = Upvote(post=some_post, user=some_user)
    # Create the upvote

Edit
Regarding your error, when you are creating or querying a new instance of a model with a foreign key, you should pass an instance of the foreign key, not the class itself. You are now:

upvote = Upvote(post=Post, user=current_user)
# Notice the Post

The Post is the definition of the class Post. What you should do is create/obtain an instance of the class Post and pass it along. such as:

post_instance = Post.objects.get(pk=2) # Or whatever query you might need to use or even creating a new post
upvote = Upvote(post=post_instance, user=current_user)

Upvotes: 1

Alvaro Bataller
Alvaro Bataller

Reputation: 483

For this type of data usually is best to create a new model, for example, called "Upvotes" which will have 3 fields:

class Upvotes(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    post = models.ForeignKey(Post, on_delete=models.CASCADE)
    timestamp = models.DateTimeField(auto_now_add=True)

This way you will create a table that will contain all the users that have upvoted a comment and which comment they have upvoted, including the date and time.

I hope it helps.

Upvotes: 1

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