CODEWITHSUNDEEP
ruby-on-railsrubyruby-on-rails-3associations
Backo
Backo

Reputation: 18871

Retrieve only 'id' values from a Record Association

I am using Ruby on Rails 3.0.7 and I have an "User :has_many Articles" Record Association for which I retrieve user's articles in this way:

@user.articles
# => [#<Article id: 1, title: "Title 1">, #<Article id: 2, title: "Title 2">, #<Article id: ..., title: "Title ...">]

However, for what I need to do, I would like to retrieve only article's id values from that association. BTW: It should be a more performant operation of the above.

How is it possible to do that in an "direct" way? That is, there is a Ruby on Rails method to accomplish that by keeping unchanged the :has_many association statement for both involved models? If so, how?

Upvotes: 4

Views: 1424

Answers (2)

Anno2001
Anno2001

Reputation: 1363

gotcha: 

@user.article_ids<< new_id

does not work, it seems to be a read-only array

Upvotes: 0

Heikki
Heikki

Reputation: 15417

http://guides.rubyonrails.org/association_basics.html#has_many-collection_singular

@user.article_ids

Upvotes: 6

Related Questions