rails--rails/activerecord/test/fixtures/author.rb

class Author < ActiveRecord::Base
  has_many :posts
  has_many :posts_with_comments, :include => :comments, :class_name => "Post"
  has_many :posts_with_categories, :include => :categories, :class_name => "Post"
  has_many :posts_with_comments_and_categories, :include => [ :comments, :categories ], :order => "posts.id", :class_name => "Post"
  has_many :comments, :through => :posts
  has_many :funky_comments, :through => :posts, :source => :comments

  has_many :special_posts,        :class_name => "Post"
  has_many :hello_posts,          :class_name => "Post", :conditions=>"\#{aliased_table_name}.body = 'hello'"
  has_many :nonexistent_posts,    :class_name => "Post", :conditions=>"\#{aliased_table_name}.body = 'nonexistent'"
  has_many :posts_with_callbacks, :class_name => "Post", :before_add => :log_before_adding,
           :after_add     => :log_after_adding, 
           :before_remove => :log_before_removing,
           :after_remove  => :log_after_removing
  has_many :posts_with_proc_callbacks, :class_name => "Post",
           :before_add    => Proc.new {|o, r| o.post_log << "before_adding#{r.id}"},
           :after_add     => Proc.new {|o, r| o.post_log << "after_adding#{r.id}"},
           :before_remove => Proc.new {|o, r| o.post_log << "before_removing#{r.id}"},
           :after_remove  => Proc.new {|o, r| o.post_log << "after_removing#{r.id}"}
  has_many :posts_with_multiple_callbacks, :class_name => "Post",
           :before_add => [:log_before_adding, Proc.new {|o, r| o.post_log << "before_adding_proc#{r.id}"}],
           :after_add  => [:log_after_adding,  Proc.new {|o, r| o.post_log << "after_adding_proc#{r.id}"}]
  has_many :unchangable_posts, :class_name => "Post", :before_add => :raise_exception, :after_add => :log_after_adding

  has_many :categorizations
  has_many :categories, :through => :categorizations

  has_many :nothings, :through => :kateggorisatons, :class_name => 'Category'

  has_many :author_favorites
  has_many :favorite_authors, :through => :author_favorites, :order => 'name'

  has_many :tagging,  :through => :posts # through polymorphic has_one
  has_many :taggings, :through => :posts, :source => :taggings # through polymorphic has_many
  has_many :tags,     :through => :posts # through has_many :through
  has_many :post_categories, :through => :posts, :source => :categories

  belongs_to :author_address

  attr_accessor :post_log

  def after_initialize
    @post_log = []
  end

  private
    def log_before_adding(object)
      @post_log << "before_adding#{object.id}"
    end

    def log_after_adding(object)
      @post_log << "after_adding#{object.id}"
    end

    def log_before_removing(object)
      @post_log << "before_removing#{object.id}"
    end

    def log_after_removing(object)
      @post_log << "after_removing#{object.id}"
    end

    def raise_exception(object)
      raise Exception.new("You can't add a post")
    end
end

class AuthorAddress < ActiveRecord::Base
  has_one :author
end

class AuthorFavorite < ActiveRecord::Base
  belongs_to :author
  belongs_to :favorite_author, :class_name => "Author", :foreign_key => 'favorite_author_id'
end