issue with eager loading in nested routes

rubyonrails-talk
1

Hi Everyone,

I have issue while doing eager loading when url is => http://127.0.0.1:3001/projects/1/features I also did <%= debug @features %> to dump @feature object but I did not see 'owner' being eager-loaded.

Can anyone find out why owner is not being 'eager-loaded'?

Thanks in advance.

========= features_controller.rb -> index method

  def index     @project = Project.find(params[:project_id])     @features = @project.features.find(:all, :include => [:owner, :project])

    respond_to do |format|       format.html # index.html.erb       format.xml { render :xml => @features }     end   end

========= Output of <%= debug @features %>

2

Does the owner exist at all ? remove the :include, if the exception persists then you know eager loading is not at fault.

Fred

3

Fred, owner do exist.

class Feature < ActiveRecord::Base   belongs_to :project   belongs_to :owner, :class_name => "User", :foreign_key => "owner_id" end

Now in features controller, I have

@features = @project.features.find(:all, :include => :owner)

and dump for @features in view is where i see only two features being loaded and not the corresponding owner (only 1 in this case, with id 1) -

4

Hi --

5

Oops I had removed that myself. Damn!

Consider this please -

Now in features controller, I have @features = @project.features.find(:all, :include => :owner) and dump for @features in view is where i see only two features being loaded and not the corresponding owner (only 1 in this case, with id 1) -

6

In server log, I do see query for fetching users with id=1. How this is not appearing in the index view??

========= Server Log

Processing FeaturesController#index (for 127.0.0.1 at 2009-10-24 19:42:45) [GET]   Parameters: {"project_id"=>"1"}   e[4;36;1mProject Columns (0.0ms)e[0m e[0;1mSHOW FIELDS FROM `projects`e[0m   e[4;35;1mProject Load (0.0ms)e[0m e[0mSELECT * FROM `projects` WHERE (`projects`.`id` = 1) e[0m   e[4;36;1mFeature Load (0.0ms)e[0m e[0;1mSELECT * FROM `features` WHERE (`features`.project_id = 1) e[0m   e[4;35;1mFeature Columns (16.0ms)e[0m e[0mSHOW FIELDS FROM `features`e[0m   e[4;36;1mUser Columns (16.0ms)e[0m e[0;1mSHOW FIELDS FROM `users`e [0m   e[4;35;1mUser Load (0.0ms)e[0m e[0mSELECT * FROM `users` WHERE (`users`.`id` = 1) e[0m Rendering template within layouts/features Rendering features/index   e[4;36;1mCACHE (0.0ms)e[0m e[0;1mSELECT * FROM `projects` WHERE (`projects`.`id` = 1) e[0m   e[4;35;1mCACHE (0.0ms)e[0m e[0mSELECT * FROM `projects` WHERE (`projects`.`id` = 1) e[0m Rendered common/_main_menu (16.0ms) Rendered common/_project_menu (0.0ms) Completed in 141ms (View: 47, DB: 32) | 200 OK [http://127.0.0.1/ projects/1/features]

7

In server log, I do see query for fetching users with id=1. How this is not appearing in the index view??

Is there a user with id 1? Get it working without :include, then worry about the eager loading.

Fred

8

Fred, thanks! there s no user with id 1. My bad!

While destroying a record, is there any easier way (a hook in activerecord) to get warning/error that record belongs to other records (if at all it does)?

9

You can set a dependent option on associations to control this sort of stuff. If you want a real guarantee that this can't ever happen, use a foreign key constraint.

Fred