class method or named_scope?
- by Hadi
i would like to have your opinion in a project i am currently working on.
class Product
has_many :orders
end
class Order
attr_accessor :deliverable # to contain temporary data on how many items can be delivered for this order
belongs_to :product
end
somehow i want to have
Order.all_deliverable
that will calculate the Product's quantity, subtract from list of Orders until the Product is empty or there is no more Order for this Product
to illustrate
Product A, quantity: 20
Product B, quantity: 0
Order 1, require Product A, quantity: 12
Order 2, require Product B, quantity: 10
Order 3, require Product A, quantity: 100
so if i call Order.all_deliverable, it will give
Order 1, deliverable:12
Order 3, deliverable: 8 #(20-12)
i have been thinking on using named_scope, but i think the logic will be too complex to be put in a named_scope. Any suggestion?
the pseudo code for all_deliverable will be something like this:
go to each orders
find the remaining quantity for specific product
deduct the product to max amount of order, if product is not enough, add the maximum product
add to the order
end
From what i read around in the web, named_scope deal mostly like find and have not many method calling and looping.
