![# Set related objects
wheel_1 = Wheel.create
wheel_2 = Wheel.create
wheel_3 = Wheel.create
wheels = [wheel_1, wheel_2, wheel_3]
car.wheels = wheels
car.save
wheel_1.car_id # car.id
# Fetch array of related objects from the respective database
car.wheels # [wheel_1, wheel_2, wheel_3]
# Fetch ids of related objects from the database
car.wheel_ids # [wheel_1.id, wheel_2.id, wheel_3.id]
# Add a related object to the collection
new_wheel = Wheel.create
car.wheels << new_wheel
car.save
car.wheels # [wheel_1, wheel_2, wheel_3, new_wheel]](https://image.slidesharecdn.com/tenacity-110621070506-phpapp02/85/Tenacity-11-320.jpg)
Tenacity
- 1. Tenacity https://github.com/jwood/tenacity ChicagoDB June 20, 2011
- 2. Polyglot Persistence is Great! Managing relationships...not so much
- 3. class Car include MongoMapper::Document def wheels Wheel.where(:car_id => self.id) end end class Wheel < ActiveRecord::Base # car_id defined on the table def car Car.find(self.car_id) end end
- 4. Problems • Lots of boilerplate code • Bogus values can be stored in car_id • What happens if the Car is deleted? • Objects fetched from the database each time • Adding new wheels is awkward
- 5. Introducing Tenacity • Heavily based on ActiveRecord::Associations • Support for has one, belongs to, and has many relationships • Adds foreign key like behavior • Can “clean up” when objects are deleted • Related objects are fetched from the database once and then cached
- 6. Introducing Tenacity • Easily work with collections of associated objects • Polymorphic associations • Read only associations • Support for a wide array of popular Ruby ORM/ODM libraries
- 7. class Car include MongoMapper::Document def wheels Wheel.where(:car_id => self.id) end end class Wheel < ActiveRecord::Base # car_id defined on the table def car Car.find(self.car_id) end end
- 8. class Car include MongoMapper::Document include Tenacity t_has_many :wheels end class Wheel < ActiveRecord::Base include Tenacity t_belongs_to :car end
- 9. class Car include MongoMapper::Document include Tenacity t_has_many :wheels t_has_one :dashboard end class Wheel < ActiveRecord::Base include Tenacity t_belongs_to :car end class Dashboard < CouchRest::Model::Base include Tenacity use_database MY_DATABASE t_belongs_to :car end
- 10. car = Car.create # Set the related object dashboard = Dashboard.create car.dashboard = dashboard car.save # Fetch related object from the respective database car.dashboard # Fetch related object id car.dashboard.car_id
- 11. # Set related objects wheel_1 = Wheel.create wheel_2 = Wheel.create wheel_3 = Wheel.create wheels = [wheel_1, wheel_2, wheel_3] car.wheels = wheels car.save wheel_1.car_id # car.id # Fetch array of related objects from the respective database car.wheels # [wheel_1, wheel_2, wheel_3] # Fetch ids of related objects from the database car.wheel_ids # [wheel_1.id, wheel_2.id, wheel_3.id] # Add a related object to the collection new_wheel = Wheel.create car.wheels << new_wheel car.save car.wheels # [wheel_1, wheel_2, wheel_3, new_wheel]
- 12. How Does It Work? • Extends supported libraries with a common set of methods • Tenacity uses these methods to work with the objects in a generic fashion • Methods are added to the model class to interact with the relationship • ORM/ODM callback functionality is used to trigger Tenacity to save associated objects, cleanup associations, etc
- 13. Supported Libraries • ActiveRecord • MongoMapper (2.x and 3.x) • Mongoid • CouchRest • Ripple (CouchModel and ExtendedDocument) • Sequel • DataMapper • Toystore
- 14. What’s On Deck? • Add support for many to many associations • Add support for build and create methods • Author.posts.build • Improve performance • Continue adding support for additional ORM/ ODM libraries
- 15. Thanks! john@johnpwood.net @johnpwood