Question

I have a couple of models that are composites of multiple objects. I basically manage them manually for saves and updates. However, when I select items out, I don’t have access to the associated properties of said item. For example:

class ObjectConnection < ActiveRecord::Base
  def self.get_three_by_location_id location_id
    l=ObjectConnection.find_all_by_location_id(location_id).first(3)
    r=[]
    l.each_with_index do |value, key|
      value[:engine_item]=Item.find(value.engine_id)
      value[:chassis_item]=Item.find(value.chassis_id)
      r << value
    end
    return r
  end
end

and each item:

class Item < ActiveRecord::Base
  has_many :assets, :as => :assetable, :dependent => :destroy

When I use the ObjectLocation.find_three_by_location_id, I don’t have access to assets whereas if use Item.find(id) in most other situations, I do.

I tried using includes but that didn’t seem to do it.

thx

Answer 1

Sounds like the simplest solution would be to add methods to your ObjectConnection model for easy access like so:

class ObjectConnection < ActiveRecord::Base

  def engine
    Engine.find(engine_id)
  end

  def chassis
    Chassis.find(chassis_id)
  end

  # rest of class omitted...

I’m not exactly sure what you’re asking… If this doesn’t answer what you’re asking, then can you try to be a little bit more clear with what exactly you are trying to accomplish? Are the Chassis and Engine mdoels supposed to be polymorphic associations with your Item model?

Also, the code you’re using above won’t work due to the fact that you are trying to dynamically set properties on a model. It’s not your calls to Item.find that are failing, it’s your calls to value[:engine_item]= and value[:chassis_item] that are failing. You would need to modify it to be something like this if you wanted to keep that flow:

def self.get_three_by_location_id location_id
  l=ObjectConnection.find_all_by_location_id(location_id).first(3)
  r=[]
  l.each_with_index do |obj_conn, key|
    # at this point, obj_conn is an ActiveRecord object class, you can't dynamically set attributes on it at this point
    value = obj_conn.attributes # returns the attributes of the ObjectConnection as a hash where you can then add additional key/value pairs like on the next 2 lines
    value[:engine_item]=Item.find(value.engine_id)
    value[:chassis_item]=Item.find(value.chassis_id)
    r << value
  end
  r
end

But I still think that this whole method seems unnecessary due to the fact that if you setup proper associations on your ObjectConnection model to begin with, then you don’t need to go and try to handle the associations manually like you’re attempting to do here.