[Fixed]-Related field nested lookup error

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One approach that can be taken is as following(I am only considering the four models you have presented in your question),

You have foreign key of Shipping company in Shipping model. So you can make use of model function here on Shipping_company model.

Take a look at this model function

class Shipping_company(models.Model):

   fields... 

   def get_profiles(self):
       shippings = Shipping.objects.filter(shipping_company=self)
       users = list(set([x.order.ship_to for x in shippings]))

Explanation:

shippings = Shipping.objects.filter(shipping_company=self)

will return all the shippings for one Shipping company(FedEx in your case). Further loop through the shippings to get ship_to from order field.

PS: You can take it as reference and design your own solution.

Walkthrough:

Lets say there is shipping company ‘FedEx’. So we do,

fedex = Shipping_company.objects.get(name='FedEx')

Now, when you call get_profiles on fedex, like 

fedex.get_profiles()

what will happen is this.

fedex instance refers to self in get_profiles() function now.
Using self(fedex), we filter out shippings by fedex.
Then we loop through those shippings to get order per shipping and each of that order has a ship_to(profile) foreign key.

I guess, you are getting confused because of the return statement.

In elaborate fashion the whole function will look something like this

def get_profiles(self):
    users = list()
    shippings = Shipping.objects.filter(shipping_company=self)
    for shipping in shippings:
        order = shipping.order
        #Now you have an order per shipping, so you do
        if not order.ship_to in users:
            users.append(order.ship_to)
    return users
👤Rajesh Yogeshwar

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