CODEWITHSUNDEEP
django
xpanta
xpanta

Reputation: 8418

django retrieveing user objects

I have a simple model like this:

class Auction(models.Model):
    name = models.CharField()

class Item(models.Model):
    auction = models.ForeignKey(Auction)
    name = models.CharField()
    price = models.FloatField()

class Bid(models.Model):
    item = models.ForeignKey(Item)
    user = models.ForeignKey(User)
    price = models.FloatField()

users place bids for an item. Knowing that a user is allowed to place just one bid for each item. If I have the auction id, can I get all user objects (not simple usernames, like in a values_list()) that placed a bid in that auction?

EDIT: I would also like to avoid using 'in'

Upvotes: 0

Views: 126

Answers (2)

andersem
andersem

Reputation: 724

It's probably possible to do it much easier, but this is the way I would try.

Add related names: 

from django.db import models
from django.contrib.auth.models import User

class Auction(models.Model):
    name = models.CharField(max_length=20)

class Item(models.Model):
    auction = models.ForeignKey(Auction,related_name="items")
    name = models.CharField(max_length=20)
    price = models.FloatField()

class Bid(models.Model):
    item = models.ForeignKey(Item,related_name="bids")
    user = models.ForeignKey(User,related_name="bids")
    price = models.FloatField()

Now, if you have these:

a = Auction.objects.get(pk=auction_id)
users = set([]) #because there's no reason to have dupe users
for item in a.items.all():
    for bid in item.bids.all():
        users.add(bid.user)

Now, all the users with one or more bids in that auction is in the list

Upvotes: 1

Daniel Roseman
Daniel Roseman

Reputation: 599956

users = User.objects.filter(bid__item__auction_id=auction_id)

Upvotes: 4

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