diff options
Diffstat (limited to 'activerecord/lib/active_record/attribute_methods.rb')
| -rw-r--r-- | activerecord/lib/active_record/attribute_methods.rb | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/attribute_methods.rb b/activerecord/lib/active_record/attribute_methods.rb index 8f165fb1dc..b2db0ceae7 100644 --- a/activerecord/lib/active_record/attribute_methods.rb +++ b/activerecord/lib/active_record/attribute_methods.rb @@ -369,6 +369,39 @@ module ActiveRecord write_attribute(attr_name, value) end + # Returns the name of all database fields which have been read from this + # model. This can be useful in devleopment mode to determine which fields + # need to be selected. For performance critical pages, selecting only the + # required fields can be an easy performance win (assuming you aren't using + # all of the fields on the model). + # + # For example: + # + # class PostsController < ActionController::Base + # after_action :print_accessed_fields, only: :index + # + # def index + # @posts = Post.all + # end + # + # private + # + # def print_accessed_fields + # p @posts.first.accessed_fields + # end + # end + # + # Which allows you to quickly change your code to: + # + # class PostsController < ActionController::Base + # def index + # @posts = Post.select(:id, :title, :author_id, :updated_at) + # end + # end + def accessed_fields + @attributes.accessed + end + protected def clone_attribute_value(reader_method, attribute_name) # :nodoc: |