2. 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
What is Ruby on Rails?
3. • 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
RoR Trivia
4. Dynamic, high level, interpreted, pure object-
orientated language.
“Ruby is designed to make programmers happy”
Yukihiro Matsumoto aka Matz
What is Ruby?
5. • Creator of Ruby
– Yukihiro Matsumoto aka Matz
• Birthday: 24 February 1993
• Originated in Japan and Rapidly
Gaining Mindshare in US and Europe.
Ruby Trivia
8. • 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
Model - View - Controller
9. 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
10. Design Principles
Full Stack Framework
• MVC suite
• built-in webserver
• default db adapter
• AJAX, web services, email
• test framework
• plugins
11. • 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
Convention over Configuration
12. • 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
Design Principles
DRY - Don’t Repeat Yourself
15. • Object Relational Mapping
– “ActiveRecord”
• Less Database “glue” Code
• Logging for Performance Checking
MVC Architecture
Model - ActiveRecord
16. MVC Architecture
Model : Rules
• Table Names
– Plurals
• Attribute Names
– id for primary key in table
– table_id for foreign key in other table
17. 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
18. 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
