Ruby-on-rails-3 – Nested property issues in Rails 3 with Mongoid (nested objects are not saved)

class Survey
 include Mongoid::Document
 field :name 
 has_many :questions, :dependent => :destroy
 accepts_nested_attributes_for :questions, :allow_destroy => true
end

class Question
 include Mongoid:: Document
 field :content
 belongs_to :survey
end

def new
 @survey = Survey.new
 3.times {@survey.questions.build}
....

<%= form_for(@survey) do |f| %>
 <%= f.fields_for :questions do |builder| %>
 <%= builder.label :content , "Question" %>

 <%= builder.text_area :content, :rows => 3 %>

 <%= builder.check_box :_destroy %>
 <%= builder.label :_destroy, "Remove Question" %>
 <% end %>
...

Started POST "/surveys" for 127.0.0.1 at 2011-05-24 13:26:51 +0400
 Processing by SurveysController#create as HTML
 Parameters: {"utf8"=>"G£ ô", "authenticity_token"=>"tX0FfMiLbh1BwjuY4CuvAKt2UpTraY3vmdo58ocBnos=", "survey"=>{"name"=>"
Rails", "questions_attributes"=>{"0"=>{"content"=>" Are you fond of Rails?", "_destroy"=>"0"}, "1"=>{"content"=>"Rails is
 the best, ha?", "_destroy"=>"0 "}, "2"=>{"content"=>"How many railscasts have you watched?", "_destroy"=>"0"}}}, "commit
"=>"Create Survey"} 
MONGODB nested_attributes_development['surveys'].insert([{"name"=>"Rails", "_id"=>BSON::ObjectId('4ddb79dba5372914380000
69')}])
Redirected to http://localhost:3000/surveys/4ddb79dba537291438000069

MONGODB 
nested_attributes_development['surveys'].insert([{"name"=>"Rails" , 
"_id"=>BSON::ObjectId('4ddb79dba5372914380000 
69')}]) 

So I have one Simple applications, such as RailsCast about nested forms. The problem is that when I submit the form (with survey and questions), the question will not be saved.

My model (survey, there are many Questions):

class Survey
 include Mongoid::Document
 field :name
 has_many :questions, :dependent => :destroy< br /> accepts_nested_attributes_for :questions, :allow_destroy => true
end

class Question
 include Mongoid::Document
 field :content
 belongs_to :survey 
end

and survey controller:

def new
 @survey = Survey.new
 3.times {@survey.questions.build}
....

And an opinion:

<%= form_for(@survey) do |f| %>
 <%= f.fields_for :questions do |builder| %>
 <%= builder.label :content, "Question" %>

 < %= builder.text_area :content, :rows => 3 %>

 <%= buil der.check_box :_destroy %>
 <%= builder.label :_destroy, "Remove Question" %>
 <% end %>
...

In In my log, I have:

Started POST "/surveys" for 127.0.0.1 at 2011-05-24 13:26:51 +0400
 Processing by SurveysController#create as HTML
 Parameters: {"utf8"=>"G£ô", "authenticity_token"=>"tX0FfMiLbh1BwjuY4CuvAKt2UpTraY3vmdo58ocBnos=", "survey"=>{"name"=>"
 Rails", "questions_attributes"=>{"0"=>{"content"=>"Are you fond of Rails?", "_destroy"=>"0"}, "1"=>{"content"=> "Rails is
 the best, ha?", "_destroy"=>"0"}, "2"=>{"content"=>"How many railscasts have you watched?", "_destroy"=> "0"}}}, "commit
"=>"Create Survey"}
MONGODB nested_attributes_development['surveys'].insert([{"name"=>"Rails", "_id"= >BSON::ObjectId('4ddb79dba5372914380000
69')}])
Redirected to http://localhost:3000/surveys/4ddb79dba537291438000069

The answer was found in the Google team, so I just copied it:

MONGODB 
nested_attributes_development['surv eys'].insert([{"name"=>"Rails", 
"_id"=>BSON::ObjectId('4ddb79dba5372914380000 
69')}])

This will not be saved to the unfinished question collection
mongoid default.
Just add has_many:questions,:dependent =>:destroy,:autosave =>
true
this should work.
p>

Refer to http://mongoid.org/docs/upgrading.html for more details.