CODEWITHSUNDEEP
rubyruby-on-rails-3
paulus
paulus

Reputation: 655

Rails 'nested' association search

This question must have been asked million times already, but i just couldn't find the answer :(

Assuming I have 3 models:

class Country
  has_many :cities
end

class City
  has_many :companies
end

class Company
  belongs_to :city
end

I can fetch companies in the given City by City.first.companies, but what I would like is to be able to fetch all companies for given Country, like Country.first.companies

What I was able to achieve is to write a method in Country model:

 def companies
   @companies = []
   cities.all.each{ |c| @companies << c.companies unless c.companies.empty? }
   @companies
 end

But it returns array of arrays of Company objects. I could have also added country_id column as a FK for Country model, like

class Country
  has_many :cities
  has_many :companies
end

class Company
  belongs_to :city
  belongs_to :country
end

but that doesn't look very DRY.

I would like to receive array of Company objects for given Country. I'm pretty sure that there is a Rails way to achieve this. What would it be?

Thanks!

Upvotes: 0

Views: 76

Answers (1)

MurifoX
MurifoX

Reputation: 15089

Use the has_many through association. 

class Country
  has_many :companies, :through => :cities

Now you can use Country.last.companies.

Upvotes: 1

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