Rails.loves?(:mongodb) => trueA Peek Into Making Awesomely Dynamic

Applications

How Many Have Experience With Rails?

How Many Have Experience With

Databases?

How Many Have Heard Of MongoDB?

MongoDB Is...Document database (NoSql) (1) Data is stored as BSON Objects (looks exactly like JSON) Gives high performance, high availability, and easy scalability Gives you ultimate flexibility with features like...

Sweet Data Types: Hashes and Arrays Allows you to nest documents Allows for dynamic document attributes

(1) Despite the word “NoSql” you can still create a relational database with MongoDB

MongoDB In Relational TermsMongoDB MySql

Document Row

Collection Table

Database Database

Index Index

More MongoDB KnowledgeTwo types of relations:

Embedded and Referenced No such thing as a “join”, this type of thing can be achieved with embedded documents and linking Has a built in aggregation framework and map reducing support. You still have 1-1, 1-n, n-n relations

What A MongoDB Documents Look Like

How Does Rails Talk To MongoDB?

Mongoid - A Object-Document-Mapper(ODM) (1)

(1) There are other ODM’s out there for MongoDB, MongoMapper for example. I feel Mongoid is far and away the best one. Has a supportive and active maintainer named Durran Jordan.

Why Not Use ActiveRecord?

ActiveRecord does not have built in support for MongoDB. Mongoid replaces it. However, it still uses ActiveModel. You still have all the validation goodness.

Getting StartedInstall MongoDB...Kind of important

Mac:

Windows:http://docs.mongodb.org/manual/tutorial/install-mongodb-on-windows/ Ubuntu:http://docs.mongodb.org/manual/tutorial/install-mongodb-on-ubuntu/

Getting Started With Rails

Generate a new Rails 4 Application

Modify Your Gemfile

Add the following to your gemfile, then bundle (1)(2)

(1) Current public release of Mongoid doesn’t support Rails 4. To install Mongoid 4.0, point the gem to the Mongoid github project.

!(2) If your using Rails 3, use the public gem

Generate A Mongoid Configuration File

What mongoid.yml Looks Like

All Setup. What Kind of App Should We Make?

Let’s build an app that helps you track video game achievements that you completed.

What Models Do We Need To Create?system: name, short_name game: title, description, released_at, completed_at achievement: title, description, points, multiplayer, completed_at

Let’s Build A Model

Use the Rails generator as normal.

What The Model Looks Like By Default

Clean model just includes Mongoid::Document to a class.

Lets Add Some Fields

In ActiveRecord you use migrations to add and remove fields from tables. In Mongoid you declare your fields right in the model class.

How About Some Validation

Lets Make Some Relations

The Game Model

The Achievement Model

Lets Review What We Just Did

Generated our models Added the fields Added validation Made the relations

Let’s Have Some Fun in Console

Create A System

Validation works

Document Created

Create A Game For Our System

How About Another Game

Let’s Create An Achievement

How About A Multiplayer Achievement

So How Do These Look Stored In The Database?

How Do The Embedded Documents Look?

We Completed One Of Those Achievements, lets update it

Lets Store A Dynamic Field

Lets Review What We Just DidWe created a system called “Xbox One”. We created a new game via our system document, automatically creating the relation to system. We created a new game, then created the relation to system. We can find documents by providing the document ID. Created a single and multiplayer achievement for a game. Took a look and how these are stored in the database. Updated one of the achievements as completed. Updated a document with a dynamic field.

Let’s Try Some Queries

How about all the games that are completed?

How About All Games Who have Achievements With Points Greater than 10?

How About Achievements In A Game With Points Between 10 And 30

Some More Advanced Things You Can Do

Custom Validation Methods Callbacks Scoping GeoNear Queries Map Reducing Aggregation Observers

Some Resources

MongoDB.org - More information about MongoDB RubyonRails.org - Read up on Rails 4 Mongoid.org - Documentation for Mongoid

Follow Me

Github - BillWatts Twitter - @BillWatts

Thank You!Get This Project @ http://github.com/BillWatts/rails_loves_mongodb_talk

Any Questions?