Module: ActsAsKing::ClassMethods

Defined in:
lib/acts_as_king.rb

Instance Method Summary collapse

Instance Method Details

#acts_as_king(options = {}) ⇒ Object

Defines that the model should have a self referencing hierarchy. This allows you to have threaded comments or any other type of self referencing hierarchy. ActsAsKing creates a belongs_to association (parent) and has_many association (children). It also defines a kings scope for your model to return all top level records.

Options

  • :foreign_key - The foreign key used for the association. Normally this will be ‘parent_id’. Default is ‘parent_id’.

  • :counter_cache - Defines a counter_cache for the belongs_to association that is created. Set true for the default column name (ex: Comment model would be ‘comments_count’). Otherwise specify the column name you wish to use. Default is false (no counter cache).

Example

class Comment < ActiveRecord::Base
  acts_as_king
end

comment_1 = Comment.create
comment_2 = Comment.create(:parent => comment_1) # defines parent

# return an array of all top level records
Comment.kings # => [#<Comment id: 1>]

# return an array of children belonging to comment_1
comment_1.children # => [#<Comment id: 2>]

# get the parent record for comment_2
comment_2.parent # => #<Comment id: 1>



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# File 'lib/acts_as_king.rb', line 40

def acts_as_king(options = {})
  options = { :foreign_key => 'parent_id', :counter_cache => false }.merge(options)

  belongs_to :parent, :class_name => name, :foreign_key => options[:foreign_key], :counter_cache => options[:counter_cache]
  has_many :children, :class_name => name, :foreign_key => options[:foreign_key], :dependent => :destroy

  include ActsAsKing::InstanceMethods
  scope :kings, where("#{options[:foreign_key]} IS NULL")

end