Rails: ActiveRecord query based on association value

user2158382 picture user2158382 · Oct 21, 2013 · Viewed 46.8k times · Source

I have 2 models. Report and Server that have a belongs_to and has_many relationship. I created an accessor method using delegate that allows a Report to find its associated Server.company_id. Now, I want to run a query on Report that allows me to find all Report that are associated with a specific Server that has a specific company_id attribute of 5.

Here are my two models. And yes I know the current query wont work since Report does not have an attribute company_id.

And no, I dont want to store company_id inside of Report since that information doesn't belong in Report.

Report

class Report < ActiveRecord::Base

 belongs_to :server

 delegate :company_id, :to => :server

    class << self

        def method(url, base_url)
            #Report.where(company_id: 5)
        end
    end

end

Server

class Server < ActiveRecord::Base

 attr_accessible :company_id

 has_many :reports

end

Answer

KappaNossi picture KappaNossi · Oct 21, 2013

You can perform a query like this:

Report.joins(:servers).where(:servers => {:company_id => 5})

To me, this is the cleaner solution to raw SQL.