I get the error Unknown key(s): counter_cache
when trying to implement a counter cache column in my RoR app.
I 开发者_如何学编程implemented the model associations in this question: Model association question
Here's my migration:
class AddVideoVotesCountToVideos < ActiveRecord::Migration
def self.up
add_column :videos, :video_votes_count, :integer, :default => 0
Video.reset_column_information
Video.find(:all).each do |p|
p.update_attributes :videos_votes_count, p.video_votes.length
end
end
def self.down
remove_column :videos, :video_votes_count
end
end
However, after watching http://media.railscasts.com/videos/023_counter_cache_column.mov I thought that maybe I had to move :counter_cache => true
into the VideoVote model after belongs_to :video
. However, when I do that, I get the error:
wrong number of arguments (2 for 1)
What am I doing wrong?
update_attribute
not update_attribteS
p.update_attribute :videos_votes_count, p.video_votes.length
or with update_attributes
:
p.update_attributes( :video_votes_count => p.video_votes.length )
UPD 1
:counter_cache => true
should be at the VideoVote class:
class VideoVote < ActiveRecord::Base
belongs_to :user
belongs_to :video, :counter_cache => true
end
To do counter_caching,you need to run the migration first that fills in the count columns BEFORE you include the counter_cache statement in the model. Once in the model, the columns are read only.
To avoid read-only errors while running this migration, you should use reset_counters:
Video.find_each do |video|
Video.reset_counters video.id, :video_votes
end
Rewriting Rajive Jain's solution :
Remove :counter_cache => true
statement from the model file.
Rerun the migration : rake db:migrate
Add the counter_cache statement in your model : :counter_cache => true
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