Question

I have this:

class User < ActiveRecord::Base
  has_many :serials
  has_many :sites, :through => :series
end

class Serial < ActiveRecord::Base
  belongs_to :user
  belongs_to :site
  has_many :episodes
end

class Site < ActiveRecord::Base
  has_many :serials
  has_many :users, :through => :serials
end

class Episode < ActiveRecord::Base
  belongs_to :serial
end

I would like to do some operations on User.serials.episodes but I know this would mean all sorts of clever tricks. I could in theory just put all the episode data into serial (denormalize) and then group_by Site when needed.

If I have a lot of episodes that I need to query on would this be a bad idea?

thanks

Answer 1

I wouldn’t bother denormalizing.

If you need to look at counts, you can check out counter_cache on the relationship to save querying for that.

Do you have proper indexes on your foreign keys? If so, pulling the data from one extra join shouldn’t be that big of a deal, but you might need to drop down to SQL to get all the results in one query without iterating over .serials:

User.serials.collect { |s| s.episodes }.uniq  # ack! this could be bad