Question

I have the two following models associated:

class Post < ActiveRecord::Base
  belongs_to :language
end

class Language < ActiveRecord::Base
  has_many :posts
end

From a view I have a link to filter the posts by language:

<div id="english"><%= link_to "English", {:controller => 'posts', :action => 'search_result', :language => "english"} %></div>

The model language has a variable name:string which is the one i am using to make the active record query.

The doubt i have is how i can make this query from the post controller to retrieve the right posts which has a field: language.name == “english”.

I tried this:

@posts = Post.all(:conditions => ["language.name = ?", params[:language]])

and also this:

@posts = Post.where(:language.name => params[:language])

Hope i have explained well the issue, i am a quite newbie yet. Ah! i would also know what would it be better in this case to use: “all” or “where” ??.
Thanks a lot in advance.

Answer 1

You need to do a join: http://guides.rubyonrails.org/active_record_querying.html#specifying-conditions-on-the-joined-tables

If I have understood your models/database structure correctly, the ActiveRecord call should looks something like:

Post.joins(:language).where('languages.name' => params[:language])

Hope that helps.

PS. The where call is the preferred method these days.