From: Jay Crouch <jay.crouch@...>
Date: 2010-01-23T10:02:03+09:00
Subject: 

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Hello,

I'm new to ruby/rails and am building out models right now.

My question is when extending a has_many attribute of a model as shown below does this cause 2 sequential sql selects, or just one?. Also I am wondering what methods are available on the result... i.e. are all the methods available to has_many available (such as length or clear) to the result of the sub method.

class Prospect < ActiveRecord::Base
  has_many :invitations do
    def of_campaign(campaign_id)
      find :all, :conditions => ['campaign_id = ?', campaign_id]
    end
  end
end

#...some controller...
AProspect.invitations.of_campaign(1)...
#...

> I'm pretty sure the above ruby executes: SELECT * FROM invitations WHERE prospect_id = # AND campaign_id = #
> But I'm not sure if it also executes SELECT * FROM invitations WHERE prospect_id = # 
> Also, I'm not clear as to what methods would be available to the result of 'of_campaign'... would all the has_many methods like length and clear be available.

Thanks in advance for any help/clarification.
Jay Crouch

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