The 10 Most Underused ActiveRecord::Relation Methods

gistfile1.rb

# http://blog.mitchcrowe.com/blog/2012/04/14/10-most-underused-activerecord-relation-methods/
1. Merge
class Account < ActiveRecord::Base
  # ...

  # Returns all the accounts that have unread messages.
  def self.with_unread_messages
    joins(:messages).merge( Message.unread )
  end
end

3. scoping
Comment.where(:post_id => 1).scoping do
  Comment.first # SELECT * FROM comments WHERE post_id = 1
end


6. find_each
Book.where(:published => true).find_each do |book|
  puts "Do something with #{book.title} here!"
end