Question

I have collection_select in one of my views, which properly creates a HTML <select> menu, but when I select an option it does not save in the database. In the same view I have other fields from the same db table and they save up. Here are my models:

class TrainingPart < ActiveRecord::Base
  belongs_to :activity
  belongs_to :training  
  accepts_nested_attributes_for :activity, :allow_destroy => true
end

class Activity < ActiveRecord::Base
  has_many :training_parts 
end

The partial is:

<div class="part">
  <%= f.label :activity, "Activity" %>
  <%= collection_select :training_part, :activity_id, Activity.all, :id, :name %>
  <%= f.text_field :activity_id %>
  <%= f.text_field :amount %>  
</div> 

The amount field works fine.

EDIT: I don’t use attr_accessible in any model, so all of the fields in all tables are accessible. (reference: Rails mass assignment definition and attr_accessible use)

Answer 1

I managed to do it. It turned out that I had 2 mistakes:

1) I had to remove <%= f.text_field :activity_id %> from the view as this was the field, which I was trying to set with the select menu.

2) I should’ve used f.collection_select instead of collection_select