Loop through queryset and store data

Using Django Forms & APIs
21

Sorry yes, this was a subject we worked on last week :wink:

Holding has a fk to Product

class Holding(models.Model):

    product_name = models.ForeignKey(Product, on_delete=models.CASCADE)
    profile = models.ForeignKey(Profile, on_delete=models.CASCADE)
    product_holding = models.IntegerField(blank=True, null=True)
    product_price = models.FloatField(max_length=50, blank=True, null=True)

    def __str__(self):
        return str(self.product_name)
22

Ok, then for each Product, holding_set describes the Holdings for that product.

So as you’re iterating over each item in products, then item.holding_set.all() are the Holding associated with it.

23

Yep thats it, so i want to show the holding information for that product.
I want to display the price the user paid product_price and the product_holding along with current price from the results dictionary

My code is all over the place. cause i’ve been trying all different things and copied the wrong model information into the previous post. I’ve edited it.

24

You’ve got all the information you need from what’s been posted here. You should try at this point to put all the pieces together to see what you come up with.

1 Like
25

Sorry, Ken. I’m stuggling to work this out.

holdings = profile.holding_set.all() This holds all of the holdings related to the profile for each product

Holding has a FK to Product on product_name (which should be named product).

Therefore i need to access product_holding within Holding via Product using item.something?

like you said item.holding_set.all() but i dont understand what i need to pass in. item.holding_set.product_holding but this throws object has no attribute product_holding

26

this doesn’t seem right, but it works.
within in my for loop i am doing:

holding = Holding.objects.get(product_name__product_name = item.product_name)

and then within results {...holdings:holding.product_holding}

1 Like
27

Hi Ken,

I’ve decided I want to add some more data.

I have Profile Product , Holding models, and want to add a Transaction model that is linked to the Profile , and Holding model to be able to add purchased amount and price.

I’m not sure what the best way to link these models is to be able to easily present the data within a table.

Models:

class Product(models.Model):

    product_name = models.CharField(max_length=255, blank=False, unique=True)
    product_slug = models.CharField(max_length=50, blank=True,null=True)
    product_symbol = models.CharField(max_length=50, blank=True,null=True)
    product_price = models.FloatField(blank=True,null=True)
    product_capture_date = models.DateField(blank=True,null=True)
    product_logo_address = models.URLField(max_length=255, blank=True)

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

class Profile(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE)
    bio = models.TextField(max_length=500, blank=True)
    location = models.CharField(max_length=30, blank=True)
    birth_date = models.DateField(null=True, blank=True)
    products = models.ManyToManyField(Product, blank=True, through='Holding')
    ....

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

class Holding(models.Model):

    product_name = models.ForeignKey(Product, on_delete=models.CASCADE)
    profile = models.ForeignKey(Profile, on_delete=models.CASCADE)
    product_holding = models.FloatField(max_length=50, blank=True, null=True)

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

class Transaction(models.Model):

    product = models.ForeignKey(Holding, on_delete=models.CASCADE)
    amount = models.FloatField(max_length=50, blank=True, null=True)
    price = models.FloatField(max_length=50, blank=True, null=True)
    transaction_date = models.DateField(null=True, blank=True)
    profile = models.ForeignKey(Profile, on_delete=models.CASCADE)

I’ve created the transaction model and linked it with a FK to Holding and Profile - this seems to work for allocating the data to the model and allows me to add multiple transactions to a product for a profile.

But I think there is a better way to work within the view, bearing in mind that a product could have multiple transactions assigned and i wouldn’t all the transactions listed just the total amount and average price.

profile = Profile.objects.get(user = request.user)
transact = Transaction.objects.filter(profile = profile)

So within my table, I want to show the product_name , transaction.price , and product_holding . within the same view.

    for item in products:
        if item.product_slug is not None:
            data = pt.get_product_by_id(item.product_slug)
            price = (data['market_data']['current_price']['GBP'])
            day_change_percentage = (data['market_data']['price_change_percentage_24h'])
            results.append({'price':price,'day_change_percentage':day_change_percentage})
...
        else:
            pass

Im trying

     transactions = Transaction.objects.filter(product_name__product_name = item_product_name)

within the for item in products

28

Fixed this.

transactions = Transaction.objects.filter(product__product_name_id = item.id)