A brief introduction to Ruby on Rails.

2. Ruby © Vita Rara, Inc. “ I always knew one day Smalltalk would replace Java. I just didn’t know it would be called Ruby.” - Kent Beck, Creator of “Extreme Programming”

12. Migration Example © Vita Rara, Inc. create_table "users" , :force => true do |t| t.string :login, :email, :remember_token t.string :salt, :crypted_password, :limit => 40 t.timestamps t.datetime :remember_token_expires_at end

15. ActiveRecord Model Example © Vita Rara, Inc. create_table &quot;persons&quot; do |t| t.string :first_name, last_name t.timestamps end class Person < ActiveRecord::Base end p = Person.new p.first_name = ‘Mark’ p.last_name = ‘Menard’ p.save

23. ActiveRecord Associations © Vita Rara, Inc. # Has Many class Order < ActiveRecord::Base has_many :order_line_items end class OrderLineItem < ActiveRecord::Base belongs_to :order end # Has One class Party < ActiveRecord::Base has_one :login_credential end class LoginCredential < ActiveRecord::Base belongs_to :party end

28. Validation Example © Vita Rara, Inc. class Person < ActiveRecord::Base def validate puts “validate invoked” end def validate_on_create puts “validate_on_create invoked” end def validate_on_update puts “validate_on_update invoked” end end peter = Person.create(:name => “Peter”) # => validate, validate_on_create invoked peter.last_name = “Forsberg” peter.save # => validate_on_update invoked

30. Validation Macro Example © Vita Rara, Inc. class User < ActiveRecord::Base validates_presence_of :name, :email, :password validates_format_of :name, :with => /^ +$/ , :message => “may only contain word characters” validates_uniqueness_of :name, :message => “is already in use” validates_length_of :password, :within => 4 .. 40 validates_confirmation_of :password validates_inclusion_of :role, :in => %w(super admin user) , :message => “must be super , admin, or user”, :allow_nil => true validates_presence_of :customer_id, :if => Proc. new { |u| %w(admin user) .include?(u.role) } validates_numericality_of :weight, :only_integer => true, :allow_nil => true end

34. A Simple Controller © Vita Rara, Inc. class PrioritiesController < InternalController def show @priority = current_account.priorities.find(params[:id]) end def new @priority = Priority. new end def create @priority = Priority. new (params[:priority]) if @priority.save flash[:notice] = 'The priority was successfully created.' redirect_to account_url else render :action => &quot;new&quot; end end ... end

41. Example View © Vita Rara, Inc. <p> <b>Name:</b> <%=h @category.name %> </p> <%= link_to 'Edit' , edit_category_path(@category) %> | <%= link_to 'Back' , categories_path %>

42. A Check Book Ledger Example

45. Shameless Self Promotion