A cheat sheet for making Rails ActiveRecord relations while using some models from the Spree framework.

rails-relation.rb

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# Relationship: One-to-One
# Tables: Instructor - Spree::User
# User has one Instructor
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# in app/models/instructor.rb
class Instructor < ActiveRecord::Base
  belongs_to :spree_user, :class_name => 'Spree::User'
end
# in migration file:
class CreateInstructors < ActiveRecord::Migration
  def change
    create_table :instructors do |t|
      t.string :employee_number
      t.belongs_to :spree_user, index: true
      t.timestamps null: false
    end
  end
end

# In app/models/spree/user_decorator.rb
module Spree
  User.class_eval do
    has_one :instructor
  end
end

###
# Accessing via: rails console
##
user = Spree::User.create(email: "[email protected]", password:"123456")
user.save
instructor = Instructor.create(spree_user_id: user.id)
instructor.spree_user  # => prints out user fields

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