Simply Rails 2 - Counter Cache - please help!

Ruby
1

Hi all,

I’m currently working through Simply Rails 2 and have come across a problem when trying to implement the Counter Cache in chapter 9.

After following the counter cache instructions (which I’ve now gone through 3 times! and checked against the source code from SitePoint) I get this error when attempting to load the Stories page in Shovell

ActiveRecord::StatementInvalid in StoriesController#index

SQLite3::SQLException: no such column: votes_count: SELECT * FROM stories WHERE (votes_count >= 1) ORDER BY id DESC

Could anyone give me some pointers as to where I might be going wrong? Obviously the column hasn’t been created by my AddCounterCacheToStories migration file but I don’t know why.

When I run db:migrate AddCounterCacheToStories (which I think would only migrate this file - sorry newbie!) then I get the error "rake aborted! Don’t know how to build task ‘AddCounterCacheToStories’.

The code in the file is;

class AddCounterCacheToStories < ActiveRecord::Migration
  def self.up
    add_column :stories, :votes_count, :integer, :default => 0
	Story.find(:all).each do |s|
	  s.update_attribute :votes_count, s.votes.length
	end
  end

  def self.down
    remove_column :stories, :votes_count
  end
end
2

Check your schema.rb file to see if your data structure is right. Sounds like the migration is failing.

3

Sorry for the late reply!

Yes the column isn’t in the schema.rb because the migration fails. I’ve gone through the previous chapter of the book again and I get the same error on the Counter Cache section!

4

“When I run db:migrate AddCounterCacheToStories”

You should just be able to run “rake db:migrate”, no? At least that’s how it’s done in rails 3…

You shouldn’t need to specify the name of the migration I don’t think