This document discusses using MongoDB with Rails applications. It provides an overview of MongoDB concepts like documents, collections, references, and embeds. It also covers using the Mongoid ORM with Rails to interact with MongoDB, including modeling, persistence, querying, references, and embeds. The document concludes by mentioning cloud hosting on MongoHQ and notes that Rails and MongoDB are a good combination.

1. Rails + MongoDB = <3
Sérgio Santos
@sdsantos
Improve Coimbra

2. Introduction / Disclamer

3. Bundlr MongoDB stats
MongoDB from the start
~ 3½ years of development
~ 6 GB of data
~ 6 million documents
Cloud hosted on MongoHQ

4. MongoDB 101

5. Documents

6. Collections

7. References

8. Embeds

9. Rails MongoDB ORMs

10. Mongoid vs MongoMapper

11. Mongoid

12. Models
class Person
include Mongoid::Document
end
person = Person.new
person[:name] = 'Sérgio'
person[:age] = 26
person.save

13. Models
class Person
include Mongoid::Document
field :name, type: String
field :age, type: Integer
end
person = Person.new
person.name = 'Sérgio'
person.age = 26
person.save

14. Persistence
person = Person.create(name: 'Sérgio', age: 26)
person.update_attributes(name: 'Sérgio Santos')
person.touch
person.delete
person.destroy
person.rename(:name, :first_name)

15. Querying
person = Person.find("4baa56f1230048567300485c")
people = Person.where(age: 18)
people = Person.where(name: 'Sérgio').not(age: 26)
Person.count
Person.all.avg(:age)
-- INSERT MAP/REDUCE CLEVER EXAMPLE HERE --

16. References
class Band
include Mongoid::Document
has_many :members
end
class Member
include Mongoid::Document
field :name, type: String
belongs_to :band
end

17. References
# The parent band document.
{
"_id" : ObjectId("4d3ed089fb60ab534684b7e9")
}
# The child member document.
{
"_id" : ObjectId("4d3ed089fb60ab534684b7f1"),
"name" : "Matt Berninger"
"band_id" : ObjectId("4d3ed089fb60ab534684b7e9")
}

18. Embeds
class Band
include Mongoid::Document
embeds_many :albums
end
class Album
include Mongoid::Document
field :name, type: String
embedded_in :band
end

19. Embeds
{
"_id" : ObjectId("4d3ed089fb60ab534684b7e9"),
"albums" : [
{
"_id" : ObjectId("4d3ed089fb60ab534684b7e0"),
"name" : "Boxer",
}
]
}

20. Extras
identity map & cache
paranoia
versioning
timestamps
geo
full text search

21. Cloud Hosting

23. Wrapping up…

24. Rails + MongoDB = <3
Sérgio Santos
@sdsantos
me@sergiosantos.info
We’re hiring!
nourishcare.co.uk/careers/