耙任务为散列抛出错误分配默认值

Question

I have a serialized attribute preferences inside the model User which looks like this :

user.preferences
=> 
 @allow_fans=true,
 @approvals={:email=>true, :message=>false},
 @comment_on_an_item={:email=>false, :message=>true},
 @community_invitations={:email=>true, :message=>true},
 @community_requests={:email=>true, :message=>true},
 @flags={:email=>true, :message=>true},
 @follows={:email=>false, :message=>true},
 @likes_and_shares={:email=>false, :message=>true},
 @make_my_email_visible=true,
 @trackbacks_pingbacks={:email=>true, :message=>false}>

I have written a rake task to assign default preferences hash to existing users like below

namespace :user_preferences do
  desc "set default preferences for existing users"
  task :pref_defaults => :environment do
    default = {:comment_on_an_item => {'email' => nil, 'message' => true},
      :likes_and_shares => {'email' => nil, 'message' => true},
      :flags => {'email' => true, 'message' => true},
      :trackbacks_pingbacks => {'email' => true, 'message' => nil},
      :community_invitations => {'email' => true, 'message' => true},
      :approvals => {'email' => nil, 'message' => true},
      :community_requests => {'email' => true, 'message' => true},
      :follows => {'email' => nil, 'message' => true}}

    User.update_all(:preferences => default)
  end
end

But when I run the rake task rake user_preferences:pref_defaults , I get the error

** Invoke user_preferences:pref_defaults (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute user_preferences:pref_defaults
rake aborted!
PG::Error: ERROR:  syntax error at or near "'---
- :likes_and_shares
- email: 
  message: true
'"
LINE 5: ','---
          ^
: UPDATE "users" SET "preferences" = '---
- :comment_on_an_item
- email: 
  message: true
','---
- :likes_and_shares
- email: 
  message: true
','---
- :flags
- email: true
  message: true
','---
- :trackbacks_pingbacks
- email: true
  message: 
','---
- :community_invitations
- email: true
  message: true
','---
- :approvals
- email: 
  message: true
','---
- :community_requests
- email: true
  message: true
','---
- :follows
- email: 
  message: true
'

Kindly help me to get through this error.

Answer 1

see comments here: http://apidock.com/rails/ActiveRecord/Base/update_all/class

If you use update_all to change an attribute marked as serialized ( using ActiveRecord::Base.serialize ), you need to call to_yaml yourself:

User.update_all({ :preferences => { :first_name => ‘John’, :last_name  => 'Doe' }.to_yaml })