Collection operations?

gistfile1.rb

# My understanding of classical OOP would suggest that this model is a better model of the business practice:

class Payment
  def process
    ###
  end
end

Class PaymentCollection
  has_many :payments
  
  def process_all_payments
    ###
  end
end

# However, with many Ruby (read: "Rails") apps, we're encouraged to tie the "multiple instances" operations into the class itself:

class Payment
  def self.process_all_payments(ids = [])
    ###
  end
  
  def process
    end
  end
end

# How does this coincide with the concept of "classical OOP"?

On line #12, did you mean for that to be a singleton method?

Nope- I was conflating the two concepts. Updated.

Thanks for the clarification!