Tame Accidental Complexity with Ruby and MongoMapper
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The document introduces MongoMapper, an ORM for MongoDB that aims to simplify Rails application development by avoiding accidental complexity. It discusses how MongoMapper handles object persistence, embedded documents, validation and callbacks. It also covers querying capabilities via Plucky and available plugins. The goal is to provide a familiar ActiveRecord-like interface while taking advantage of MongoDB's flexible data model.
![Embedded Documents
{
"_id"=>BSON::ObjectId('4d6575e84d8ff692e6000001'),
"username"=>"giordano", "password"=>"123",
"email"=>"giordano.scalzo@cleancode.it",
"tasks"=>[{
"_id"=>BSON::ObjectId('4d6575e84d8ff692e6000002'),
"description"=>"refactor server",
"pomodori"=>8, "is_done"=>false
}, {
"_id"=>BSON::ObjectId('4d6575e84d8ff692e6000003'),
"description"=>"timer sound",
"pomodori"=>2, "is_done"=>false
}]
}](https://image.slidesharecdn.com/tameaccidentalcomplexity-110225060544-phpapp02/85/Tame-Accidental-Complexity-with-Ruby-and-MongoMapper-38-320.jpg)
![Embedded Documents
{
"_id"=>BSON::ObjectId('4d6575e84d8ff692e6000001'),
"username"=>"giordano", "password"=>"123",
"email"=>"giordano.scalzo@cleancode.it",
"tasks"=>[{
"_id"=>BSON::ObjectId('4d6575e84d8ff692e6000002'),
"description"=>"refactor server",
"pomodori"=>8, "is_done"=>false
}, {
"_id"=>BSON::ObjectId('4d6575e84d8ff692e6000003'),
"description"=>"timer sound",
"pomodori"=>2, "is_done"=>false
}]
}](https://image.slidesharecdn.com/tameaccidentalcomplexity-110225060544-phpapp02/85/Tame-Accidental-Complexity-with-Ruby-and-MongoMapper-39-320.jpg)
![Documents
p User.all.last.tasks
[#<Task _id:
BSON::ObjectId('4d65822b4d8ff69542000002'),
description: "refactor server",
pomodori: 8, is_done: false,
user_id: BSON::ObjectId('4d65822b4d8ff69542000001')
>,
#<Task _id:
BSON::ObjectId('4d65822b4d8ff69542000003'),
description: "timer sound",
pomodori: 2, is_done: false,
user_id: BSON::ObjectId('4d65822b4d8ff69542000001')
>
]](https://image.slidesharecdn.com/tameaccidentalcomplexity-110225060544-phpapp02/85/Tame-Accidental-Complexity-with-Ruby-and-MongoMapper-42-320.jpg)
Tame Accidental Complexity with Ruby and MongoMapper
- 1. Tame accidental complexity Introduction to NoSQL with MongoMapper Giordano Scalzo
- 3. I’m not here to talk about performance
- 4. I’m not here to talk about scalability
- 5. but I’m here to talk about simplicity
- 6. Rails has been a first step
- 7. Anatomy of a Rails Application
- 8. Anatomy of a Rails Application view
- 9. Anatomy of a Rails Application view controller
- 10. Anatomy of a Rails Application view controller model
- 11. Different languages html+css view controller model
- 12. Different languages html+css oop view controller model
- 13. Different languages html+css oop sql view controller model
- 14. Impedance mismatch html+css oop sql view controller model
- 15. Origin of Sql SQL From Wikipedia, the free encyclopedia SQL (...), is a database computer language designed for managing data in relational database management systems (RDBMS)
- 16. Origin of Sql SQL From Wikipedia, the free encyclopedia SQL (...), is a database computer language designed for managing data in relational database management systems (RDBMS)
- 17. We need persistent objects!
- 18. We need persistent objects! class User def initialize(username, password) @username = username @password = password end end
- 19. We need persistent objects! { username: "giordano", password: "123" }
- 20. ActiveRecord tries its best
- 21. We need something different
- 22. Persistence
- 23. Persistence class User include MongoMapper::Document end
- 24. Persistence class User include MongoMapper::Document end user = User.create({ :username => "giordano", :password => "123" }) user.save
- 25. Persistence class User include MongoMapper::Document end user = User.create({ :username => "giordano", :password => "123" }) user.save puts User.all.last.to_mongo
- 26. Persistence { "_id"=>BSON::ObjectId('4d643a274d8ff683dd000001'), "username"=>"giordano", "password"=>"123" }
- 27. Types
- 28. Types class User include MongoMapper::Document key :username, String key :password , String end
- 29. Built-in Types Array, Binary, Boolean, Date, Float, Hash, Integer, Nil, ObjectId, Set, String, Time
- 30. Custom Types class DowncasedString def self.to_mongo(value) value.nil? ? nil : value.to_s.downcase end def self.from_mongo(value) value.nil? ? nil : value.to_s.downcase end end
- 31. Custom Types class User include MongoMapper::Document key :username, String key :password , String key :email, DowncasedString end
- 32. Custom Types user = User.new user.username = "giordano" user.password = "123" user.email = "[email protected]" user.save puts User.all.last.to_mongo
- 33. Custom Types { "_id"=>BSON::ObjectId('4d6442d94d8ff684d3000001'), "username"=>"giordano", "password"=>"123", "email"=>"[email protected]" }
- 35. Embedded Documents class Task include MongoMapper::EmbeddedDocument key :description, String key :pomodori, Integer key :is_done, Boolean end
- 36. Embedded Documents class User include MongoMapper::Document key :username, String key :password , String key :email, DowncasedString many :tasks end
- 37. Embedded Documents user.tasks << Task.new({ description: 'refactor server', pomodori: 8, is_done: false }) user.tasks << Task.new({ description: 'timer sound', pomodori: 2, is_done: false })
- 38. Embedded Documents { "_id"=>BSON::ObjectId('4d6575e84d8ff692e6000001'), "username"=>"giordano", "password"=>"123", "email"=>"[email protected]", "tasks"=>[{ "_id"=>BSON::ObjectId('4d6575e84d8ff692e6000002'), "description"=>"refactor server", "pomodori"=>8, "is_done"=>false }, { "_id"=>BSON::ObjectId('4d6575e84d8ff692e6000003'), "description"=>"timer sound", "pomodori"=>2, "is_done"=>false }] }
- 39. Embedded Documents { "_id"=>BSON::ObjectId('4d6575e84d8ff692e6000001'), "username"=>"giordano", "password"=>"123", "email"=>"[email protected]", "tasks"=>[{ "_id"=>BSON::ObjectId('4d6575e84d8ff692e6000002'), "description"=>"refactor server", "pomodori"=>8, "is_done"=>false }, { "_id"=>BSON::ObjectId('4d6575e84d8ff692e6000003'), "description"=>"timer sound", "pomodori"=>2, "is_done"=>false }] }
- 40. Documents class Task include MongoMapper::Document key :description, String key :pomodori, Integer key :is_done, Boolean end
- 41. Documents p User.all.last.to_mongo { "_id"=>BSON::ObjectId('4d657e924d8ff6949c000001'), "username"=>"giordano", "password"=>"123", "email"=>"[email protected]" }
- 42. Documents p User.all.last.tasks [#<Task _id: BSON::ObjectId('4d65822b4d8ff69542000002'), description: "refactor server", pomodori: 8, is_done: false, user_id: BSON::ObjectId('4d65822b4d8ff69542000001') >, #<Task _id: BSON::ObjectId('4d65822b4d8ff69542000003'), description: "timer sound", pomodori: 2, is_done: false, user_id: BSON::ObjectId('4d65822b4d8ff69542000001') > ]
- 44. Validations & Callbacks class User include MongoMapper::Document key :username, String, validates_presence_of :username key :password, String validates_presence_of :password end
- 45. Validations & Callbacks class User include MongoMapper::Document key :username, String, :required => true key :password, String, :required => true end
- 47. Validations & Callbacks before_save after_save before_create after_create before_update after_update before_validation after_validation before_validation_on_create after_validation_on_create before_validation_on_update after_validation_on_update before_destroy after_destroy validate_on_create validate_on_update validate
- 48. Validations & Callbacks forked in current gem 0.8.6 using Rails3 ActiveModel in Rails3 branch just merged
- 50. What about querying? query = User.where(:last_name.exists => true, :created_at.gte => from_date, :created_at.lt => Time.now) Plucky: ActiveRecord-like language .skip(0).limit(5) query.all
- 51. What about querying? query = User.where(:last_name.exists => true, :created_at.gte => from_date, :created_at.lt => Time.now) Plucky: ActiveRecord-like language .skip(0).limit(5) #<Plucky::Query created_at: { "$gte"=>"1", "$lt"=>2011-02-24 10:54:36 UTC}, last_name: {"$exists"=>true}, limit: 5, skip: 0>
- 52. What about querying? query = User.where(:last_name.exists => true) .where(:created_at.gte => from_date) .where(:created_at.lt => Time.now) Plucky: ActiveRecord-like language .skip(0).limit(5) #<Plucky::Query created_at: { "$gte"=>"1", "$lt"=>2011-02-24 10:54:36 UTC}, last_name: {"$exists"=>true}, limit: 5, skip: 0>
- 54. What about plugins? Accessible Modifiers Associations Pagination Caching Persistence Callbacks Protected Clone Querying Dirty Rails Document Safe Dynamic Querying Single EmbeddedDocument Collection Equality Inheritance IdentityMap Scopes Indexes Serialization Inspect Timestamps Keys Userstamps Logger Validations
- 55. Itʼs just a beginning