Rails视图/控制器has_many通过

Question

I have this relations:

class Community < ApplicationRecord
  has_many :community_people
  has_many :people, :through => :community_people
end

class CommunityPerson < ApplicationRecord
  belongs_to :community
  belongs_to :person
end

class Person < ApplicationRecord
  has_many :community_persons
  has_many :communities, :through => :community_persons
end

I can CRUD communities, but i've been searching how to in the controller/view add many people to that community, then show them but i can't find and answer.

I'll really appreciate your help!

Answer 1

The simplest way is by using the Rails form options helpers :

<%= form_for(@community) do |f| %>
  ...
  <div class="field">
    <%= f.label :person_ids %>
    <%= f.collection_select :person_ids, multiple: true %>
  </div>
<% end %>

---

class CommunityControllers
  ...

  def community_attributes
    params.permit(:foo, :bar, person_ids: [])
  end
end

But I would try to go with a less awkward and more descriptive naming scheme like:

class Community < ApplicationRecord
  has_many :citizenships
  has_many :citizens, through: :citizenships                      
end

class Citizenship < ApplicationRecord
  belongs_to :community
  belongs_to :citizen, class_name: "Person"
end

class Person < ApplicationRecord
  has_many :citizenships, foreign_key: 'citizen_id'
  has_many :communities, through: :citizenships
end