Ruby On Rails
Building Web Applications Is Fun!

What is Ruby on Rails?
Rails is a full-stack framework for developing
database-backed web applications according
to the Model-View-Control pattern.
– www.rubyonrails.org - Ruby on Rails official site

RoR Trivia
• Written in Ruby
• Creator of Ruby on Rails
– David Heinemeier Hansson
• Birth: July 2004
• Latest: 2.1.1: 4 September 2008
• Based on SmallTalk, Perl, Lisp
• Not strongly typed

What is Ruby?
Dynamic, high level, interpreted, pure object-
orientated language.
“Ruby is designed to make programmers happy”
Yukihiro Matsumoto aka Matz

Ruby Trivia
• Creator of Ruby
– Yukihiro Matsumoto aka Matz
• Birthday: 24 February 1993
• Originated in Japan and Rapidly
Gaining Mindshare in US and Europe.

Design Principles

Design Principles
Model - View - Controller
• Separate data (model) from user interface (view)
• Model
– data access and business logic
– independent of the view and controller
• View
– data presentation and user interaction
– read-only access to the model
• Controller
– handling events
– operating on model and view

Design Principles
Database Persistence
• OR mapping
– Active Record design pattern
• migrations
– incremental schema management
• multiple db adapters
– MySQL, PostgreSQL, SQLite, SQL Server, IBM DB2,
Informix, Oracle

Design Principles
Full Stack Framework
• MVC suite
• built-in webserver
• default db adapter
• AJAX, web services, email
• test framework
• plugins

Design Principles
Convention over Configuration
• fixed directory structure
– everything has its place – source files, libs, plugins,
database files, documentation etc
• file naming conventions
– e.g. camel case class name, underscore file name
• database naming conventions
– table names, primary and foreign keys
• standard configuration files
– e.g. database connections, environment setting definitions
(development, production, test)

Design Principles
DRY - Don’t Repeat Yourself
• reusing code
– e.g. view elements
• reusing data
– e.g. no need to declare table field names – can be read
from the database
• making each line of code work harder
– e.g. mini languages for specific domains
• object-relational mapping
• metaprogramming
– dynamically created methods

MVC Architecture

MVC Architecture
MVC Architecture

MVC Architecture
Model - ActiveRecord
• Object Relational Mapping
– “ActiveRecord”
• Less Database “glue” Code
• Logging for Performance Checking

MVC Architecture
Model : Rules
• Table Names
– Plurals
• Attribute Names
– id for primary key in table
– table_id for foreign key in other table

MVC Architecture
View - ActionView
• multiple template types
– oldest and basic: erb (embedded ruby), similar to e.g. jsp
– remote javascript templates
– xml templates
• easy reuse of view elements
– file inclusion – layouts, templates, partials
– multiple standard "helpers" – common html element
generators (e.g. form elements, paginators)
• easy AJAX integration

MVC Architecture
Controller : ActionController
• Method name matches view folder
– users_controller.rb works for
/views/users/***.rhtml
– called “actions”
– all view’s methods will sit there
• Ability to
– CRUD
– Flash
– Redirect

Some Comparisons

RoR vs. Java
Comparison of Rails and J2EE stacks

Usage & Support

Usage & Support
Web Servers
• Lighttpd
• Mongrel
• WEBrick
• Apache

Usage & Support
RoR Databases
• Mysql
• Oracle
• Postgre Sql
• SqlLite

Usage & Support
Websites on Rails

Usage & Support
Companies Using Rails

References
• www.slideshare.net
• www.youtube.com
• www.google.com
• http://www.netbeans.org/kb/docs/ruby/rapid-rub
• http://guides.rails.info/getting_started.html
• www.rubyonrails.org
• http://www.tutorialspoint.com/ruby-on-rails-2.1

Thank You.!!