This document provides an overview of ActiveRecord and Mongoid object document mappers for Ruby on Rails applications. It describes MongoDB as a scalable and high-performance NoSQL database without transactions or joins. It explains how Mongoid provides a similar API to ActiveRecord but is designed for MongoDB's schemaless and document-based data model. Various Mongoid associations like embeds_many and embedded_in are demonstrated through code examples. Additional MongoDB features through Mongoid like localization, GridFS for file storage, and hybrid ActiveRecord/Mongoid applications are also briefly covered.

1. ActiveRecord vs Mongoid
Иван Немытченко, 7bits, Омск

2. PHP → Ruby on Rails →freelance →
JazzCloud → Tulp → 7bits

3. 2007 - Ruby on Rails

4. 2007 - Ruby on Rails
2008 - HAML/SASS

5. 2007 - Ruby on Rails
2008 - HAML/SASS
2010 - Coffeescript

6. 2007 - Ruby on Rails
2008 - HAML/SASS
2010 - Coffeescript
2010 - Tequila → RABL

7. 2007 - Ruby on Rails
2008 - HAML/SASS
2010 - Coffeescript
2010 - Tequila → RABL
2011 - Tulp
2012 - MongoDB

8. 2007 - Ruby on Rails
2008 - HAML/SASS
2010 - Coffeescript
2010 - Tequila → RABL
2012 - ActiveRecord vs Mongoid

9. MongoDB

10. MongoDB is a scalable, high-performance, open
“ source NoSQL database
”

11. НЕТ ТРАНЗАКЦИЙ

12. НЕТ ТРАНЗАКЦИЙ
НЕТ ДЖОЙНОВ

13. Таблицы → Коллекции

14. Таблицы → Коллекции
Строки → Документы

15. { "_id" : ObjectId( "4fb8dd1324ec7c1344000003" ),
"agent" : "Ivan Nemytchenko",
"challenge" : "Introduce MongoDB documents",
"status" : "accepted"
}

16. { "_id" : ObjectId( "4fb8dd1324ec7c1344000003" ),
"agent" : "Ivan Nemytchenko",
"missions": [
{ "challenge" : "Introduce MongoDB documents",
"status" : "done"
},
{ "challenge" : "Tell the truth about MongoDB",
"status" : "considering"
}
]
}

17. Таблицы → Коллекции
Строки → Документы
Индексы → Индексы

18. Mongoid
Object Document Mapper

19. “ The philosophy of Mongoid is to provide a
familiar API to Ruby developers who have been
using Active Record or Data Mapper, while
leveraging the power of MongoDB's schemaless
and performant document-based design, dynamic
queries, and atomic modifier operations
”
Durran Jordan, автор Mongoid

20. Связи

21. has_many
has_one
belongs_to

22. has_many
has_one
belongs_to
has_and_belongs_to_many

23. has_many
has_one
belongs_to
has_and_belongs_to_many
address: organization:
{organization_ids:[1,2,3]} {address_ids:[5,3,1,10]}

24. has_many
has_one
belongs_to
has_and_belongs_to_many
has_many :through

25. has_many
has_one
belongs_to
has_and_belongs_to_many
has_many :through

26. has_many
has_one
belongs_to
has_and_belongs_to_many
has_many :through
embeds_many
embeds_one
embedded_in

27. Lets Practice!

35. class Contact class Place
include Mongoid::Document include Mongoid::Document
field :type embeds_many :contacts
field :value end
embedded_in :place
end
place.contacts << Contact.new(:type => "phone", :value => "32-14-90")
place.contacts << Contact.new(:type => "email", :value => "omskps1@rosinter.ru")
place.save

36. { "_id" : 1,
"name" : "Планета Суши"
"contacts" : [
{ "_id" : 1,
"type" : "phone", "value" : "32-14-90" },
{ "_id" : 2,
"type" : "email", "value" : "omskps1@rosinter.ru" }
]
}

37. { "_id" : 1,
"name" : "Планета Суши"
"contacts" : [
{ "_id" : 1,
"_type" : "phone", "value" : "32-14-90" },
{ "_id" : 2,
"_type" : "email", "value" : "omskps1@rosinter.ru" }
]
}

38. class Contact
class Place
include Mongoid::Document
include Mongoid::Document
field :type
embeds_many :contacts
field :value
end
embedded_in :place
end class Email < Contact
end
class Phone < Contact
end
place.contacts << Phone.new(:value => "32-14-90")
place.contacts << Email.new(:value => "omskps1@rosinter.ru")
place.save

42. Rating RatingType
embedded_in :place embedded_in :category
Place Category
embeds_many :ratings embeds_many :rating_types

43. Place
{ "_id" : 1,
"name" : "Планета Суши"
"ratings" : [
{ "_id":1, "type":"Качество обслуживания", "value":4 },
{ "_id":2, "type":"Чистота", "value":5 } ]
}
Rating RatingType
embedded_in :place embedded_in :category
Place Category
embeds_many :ratings embeds_many :rating_types

44. Place
{ "_id" : 1,
"name" : "Планета Суши"
"ratings" : [
{ "_id":1, "type":"Качество обслуживания", "value":4 },
{ "_id":2, "type":"Чистота", "value":5 } ]
}
Category
{ "_id" : 1,
"name" : "Рестораны"
"rating_types" : ["Качество обслуживания", "Чистота"]
}
Rating RatingType
embedded_in :place embedded_in :category
Place Category
embeds_many :ratings embeds_many :rating_types

45. Place
{ "_id" : 1,
"name" : "Планета Суши"
"ratings" : [
{ "_id":1, "type":"Качество обслуживания", "value":4 },
{ "_id":2, "type":"Чистота", "value":5 } ]
}
Category
{ "_id" : 1,
"name" : "Рестораны"
"rating_types" : ["Качество обслуживания", "Чистота"]
}
Place.where(:"ratings.type"=>"Чистота", :"ratings.value.gt"=>3)

49. Answer
embedded_in :question
Question Property
embedded_in :category embedded_in :place
embeds_many :answers field :question
field :answer
Category Place
embeds_many :questions embeds_many :properties

50. >> category.questions << Question.new(:value =>
'WiFi', :answers => ['есть', 'нету'])
>> place.properties << Property.new(:question =>
'WiFi', :answer => 'есть')

54. Place
{ "_id" : 1,
"name" : ".."
"contacts" : [
{ "_type" : "phone", "value" : "32-14-90" },
{ "_type" : "email", "value" : "..." }],
"ratings" : [
{ "type" : "..", "value" : ".." },
{ "type" : "..", "value" : ".." }],
"properties" : [
{ "question" : "..", "answer" : ".." }],
"categories" : ["..", ".."],
"review_ids" : [12, 34, 56]
}
Review
{ "_id" : 12,
"user_id" : 16,
"place_id" : 1,
"body" : “..”,
"comments" : [
{ "body" : "..", "user_id" : 1, "user_name" : ".." },
{ "body" : "..", "user_id" : 5, "user_name" : ".."}],
"ratings" : [
{ "type" : "..", "value" : ".." },
{ "type" : "..", "value" : ".." }]
}

55. Place Review
Contacts AuthorSummary
Ratings Ratings
Properties Comments
Categories →
User
Category Reviews →
RatingTypes
Questions
Answers

56. To embed or not to embed?
Соотношение запись/чтение
Жизненный цикл объекта
Так ли важна целостность данных?

57. Extra Stuff

58. GridFS
CarrierWave.configure do |config|
config.storage = :grid_fs
config.grid_fs_connection = Mongoid.database
config.grid_fs_host = app_config['domain']
config.grid_fs_access_url = "/gridfs"
end
class PhotoUploader < CarrierWave::Uploader::Base
storage :grid_fs
end
gem 'carrierwave-mongoid', :require => 'carrierwave/mongoid'

59. Локализация
class Person
include Mongoid::Document
field :first_name, :localize => true
field :last_name, :localize => true
end
{ "_id" : 1,
"first_name" : { "ru" : "Иван" },
"last_name" : { "ru" : "Немытченко" }
}

60. Полный фарш
class Person
include Mongoid::Document
include Mongoid::Timestamps
include Mongoid::Versioning
include Mongoid::Paranoia
field :first_name
field :last_name
key :first_name, :last_name
end

61. Гибридные приложения
class TodoLog class Todo < ActiveRecord::Base
include Mongoid::Document after_create :create_log
field :todo_id, :type => Integer after_update :create_log
field :title, :type => String
field :done, :type => Boolean private
end def create_log
TodoLog.create(
:title => title,
:done => !!done,
:todo_id => id
)
end
end
https://github.com/a2ikm/activerecord-and-mongoid-sample

62. Анти-mongoid
This tool exposes simplicity and power of
“ MongoDB and leverages its differences
”
Алексей Петрушин, автор MongoModel
http://alexeypetrushin.github.com/mongodb_model/index.html

63. Спасибо. Давайте поговорим.
@inem
inem@bk.ru