show all companies that have a job

Question

I have an association between jobs and companies where company has_many: jobs and job belongs_to: company. Now I am trying to access a page where there are only companies that have a job, so for this i have this code in my controller

def recruiting
  @companies = Company.all
end

and this is my recruiting page

<% @companies.each do |company| %> 
  <% unless company.job.nil? %>
   <%= link_to company.name, company_path(company), title: "#{company.name}" %>
<% end %> 
<% end %>

This doesn't work and gives me an error undefined method job'

This is not the best way to do it. It loops through all Company records and skip only the ones that does not have a job. You could do it directly in your SQL to save execution time. (see this answer: http://stackoverflow.com/questions/18082096/rails-4-scope-to-find-parents-with-no-children/18082147#18082147) — MrYoshiji, Jan 16 '15 at 18:33

score 4 · Accepted Answer · answered Jan 16 '15 at 18:29

4

If you want to only return companies with jobs and not have to worry about if/unless logic in the views, you can do:

def index 
  @companies = Company.joins(:jobs).uniq
end

But if you want to return companies both with and without jobs, you should be including jobs so that you aren't making a SQL call on each iteration of the loop.

@companies = Company.includes(:jobs)

answered Jan 16 '15 at 18:29

evanbikes

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this is a better answer that the one accepted, you shouldn't be filtering in records in your view layer – Rodrigo Zurek Jan 16 '15 at 19:44

score 2 · Answer 2 · answered Jan 16 '15 at 18:17

2

Please, replace <% unless company.job.nil? %> with <% if company.jobs.any? %>

answered Jan 16 '15 at 18:17

Yaro

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I have replaced with unless company.jobs.empty? and it is working – Jan 16 '15 at 18:21
that was another option :P Just if you like "unless" more than "if" :P – Yaro Jan 16 '15 at 18:21
2

This is not the best way to do it. It loops through all Company records and skip only the ones that does not have a job. You could do it directly in your SQL to save execution time – MrYoshiji Jan 16 '15 at 18:33

score 0 · Answer 3 · answered Jan 16 '15 at 18:23

0

When you have a has_one relation, the form is singular (job). In has_many, there are multiple jobs, so the form is plural.

So

company.jobs.nil?

answered Jan 16 '15 at 18:23

Michal

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show all companies that have a job

3 Answers3