ActiveRecord 4 how to user :order and :include

Question

I've just upgraded to Ruby 2.0 which by default will load ActiveRecord 4 for a Padrino app. This is fine, I'd like to take advantage of the Ruby 2.0 and AR 4 improvements. However, I'm having trouble rewriting some of the relations that worked before.

For example, this is no longer valid:

  has_many :dvd_credits, :order => 'position', :include => [:dvd_actor, :dvd_role]

It gives a deprecated warning, but the example it shows is useless: has_many :spam_comments, -> { where spam: true }, class_name: 'Comment'

Looking around I was able to find that this works by omitting the :include parameter:

has_many :dvd_credits, -> { order :position }

If I add it like so:

has_many :dvd_credits, -> { order :position, include: [:dvd_actor, :dvd_role] }

I get this error when I call that relation:

ArgumentError: Direction should be :asc or :desc

I'm still coming to grips with the changes to AR 4 but would really appreciate some help on this.

Thanks.

PS I did find this in the AR 4 page:

There's no need to use includes for immediate associations - that is, if you have Order belongs_to :customer, then the customer is eager-loaded automatically when it's needed.

Which I take it to mean that I can safely ignore the include: parameter?

But this relationship is a bit complex, it goes like this:

class Dvd < ActiveRecord::Base
  has_many :dvd_credits, -> { order :position }
  has_many :dvd_actors, :through => :dvd_credits
  has_many :dvd_roles, :through => :dvd_credits

class DvdCredit < ActiveRecord::Base
  belongs_to :dvd_actor, :inverse_of => :dvd_credits
  belongs_to :dvd_role, :inverse_of => :dvd_credits
  belongs_to :dvd, :inverse_of => :dvd_credits

class DvdActor < ActiveRecord::Base
  has_many :dvd_credits, :inverse_of => :dvd_actors
  has_many :dvds, :through => :dvd_credits

But seems to fulfill the belongs_to condition.

Answer 1

Yea, you can just ignore the :include part.