DistroPropaganda/code/rails32/e1/ar/self_association.rb
2018-11-24 13:20:20 +01:00

63 line
1.6 KiB
Ruby

#---
# Excerpted from "Agile Web Development with Rails",
# published by The Pragmatic Bookshelf.
# Copyrights apply to this code. It may not be used to create training material,
# courses, books, articles, and the like. Contact us if you are in doubt.
# We make no guarantees that this code is fit for any purpose.
# Visit http://www.pragmaticprogrammer.com/titles/rails4 for more book information.
#---
$: << File.dirname(__FILE__)
require "connect"
require "logger"
#ActiveRecord::Base.logger = Logger.new(STDERR)
require "rubygems"
require "active_record"
ActiveRecord::Schema.define do
create_table :employees, :force => true do |t|
t.string :name
t.integer :manager_id
t.integer :mentor_id
end
end
class Employee < ActiveRecord::Base
belongs_to :manager,
:class_name => "Employee",
:foreign_key => "manager_id"
belongs_to :mentor,
:class_name => "Employee",
:foreign_key => "mentor_id"
has_many :mentored_employees,
:class_name => "Employee",
:foreign_key => "mentor_id"
has_many :managed_employees,
:class_name => "Employee",
:foreign_key => "manager_id"
end
Employee.delete_all
adam = Employee.create(:name => "Adam")
beth = Employee.create(:name => "Beth")
clem = Employee.new(:name => "Clem")
clem.manager = adam
clem.mentor = beth
clem.save!
dawn = Employee.new(:name => "Dawn")
dawn.manager = adam
dawn.mentor = clem
dawn.save!
p adam.managed_employees.map {|e| e.name} # => [ "Clem", "Dawn" ]
p adam.mentored_employees # => []
p dawn.mentor.name # => "Clem"