Ruby on Rails Building Web Applications Is Fun Again!

What is Ruby on Rails? Web application framework written in Ruby Ruby is an Object Oriented scripting language Model-view-controller Database agnostic Open source Lots of nice tools, classes and methods to make development easier

Web application framework written in Ruby

Ruby is an Object Oriented scripting language

Model-view-controller

Database agnostic

Open source

Lots of nice tools, classes and methods to make development easier

The Rails Way DRY (Don’t Repeat Yourself) Convention over configuration Baked in testing Minimal code with maximum effect

DRY (Don’t Repeat Yourself)

Convention over configuration

Baked in testing

Minimal code with maximum effect

Installing Ruby, Gem and Rails Install Ruby OCI8 Driver Connect using TNSNAMES.ORA Connect using InstantClient and a URL More information on wiki.rubyonrails.com Getting Started

Installing Ruby, Gem and Rails

Install Ruby OCI8 Driver

Connect using TNSNAMES.ORA

Connect using InstantClient and a URL

More information on wiki.rubyonrails.com

Rails on Oracle Key generation assumes sequences for each table with the name ${table_name}_seq Sequence name can be changed using ActiveRecord::Base.set_sequence_name Timezones and sub-second precision not supported More info: http://wiki.rubyonrails.com/rails/pages/Oracle

Key generation assumes sequences for each table with the name ${table_name}_seq

Sequence name can be changed using ActiveRecord::Base.set_sequence_name

Timezones and sub-second precision not supported

More info: http://wiki.rubyonrails.com/rails/pages/Oracle

Building Your First App Create a new Rails app by typing: rails myapp Edit the config/database.yml Generate a model using: script/generate model MyModel Creating a model creates a class and a migration

Create a new Rails app by typing: rails myapp

Edit the config/database.yml

Generate a model using: script/generate model MyModel

Creating a model creates a class and a migration

ActiveRecord Conventions Naming convention simplifies development and encourages good database design Tables are plural, models are singular Example: Model: LineItem Table: line_items Handles non-regular pluralization such as Person/people Can be overridden, although this complicates things for the developer

Naming convention simplifies development and encourages good database design

Tables are plural, models are singular

Example:

Model: LineItem

Table: line_items

Handles non-regular pluralization such as Person/people

Can be overridden, although this complicates things for the developer

Database Migrations Database agnostic means of defining schema Lowest-common-denominator approach Ruby code with full access to ActiveRecord Methods for creating, altering and dropping tables, columns and indexes Can execute arbitrary SQL with ‘execute’ method

Database agnostic means of defining schema

Lowest-common-denominator approach

Ruby code with full access to ActiveRecord

Methods for creating, altering and dropping tables, columns and indexes

Can execute arbitrary SQL with ‘execute’ method

ActiveRecord Models Object/Relational Mapping Model classes extend from ActiveRecord::Base ActiveRecord::Base provides: Database agnostic record creation, finding, saving and removal Data validation methods Relationships All in an easy to use package Rails encourages keeping business logic in the model where it belongs AR can be used outside of web applications

Object/Relational Mapping

Model classes extend from ActiveRecord::Base

ActiveRecord::Base provides:

Database agnostic record creation, finding, saving and removal

Data validation methods

Relationships

All in an easy to use package

Rails encourages keeping business logic in the model where it belongs

AR can be used outside of web applications

Views Responsible for creating part or all of the page displayed in a browser By default uses ERb (Embedded Ruby) Other views include ‘builders’ for XML documents or RJS templates to generate JavaScript for AJAX driven views Includes elegant means for including helper functions for rendering Supports partials and components

Responsible for creating part or all of the page displayed in a browser

By default uses ERb (Embedded Ruby)

Other views include ‘builders’ for XML documents or RJS templates to generate JavaScript for AJAX driven views

Includes elegant means for including helper functions for rendering

Supports partials and components

Controllers Generate controllers with script/generate controller MyController Controllers tie the view to the model through actions Controllers also have access to “helpers” Designed for people-friendly URLs Provides caching, session management, query parsing, cookie management, pagination

Generate controllers with script/generate controller MyController

Controllers tie the view to the model through actions

Controllers also have access to “helpers”

Designed for people-friendly URLs

Provides caching, session management, query parsing, cookie management, pagination

ActiveRecord Relationships Relationships are through primary keys Supported relationship types: belongs_to (book belongs to author) has_one (book has one publisher) has_many (book has many pages) has_and_belongs_to_many (book has and belongs to many readers) has_many :through (book has many contributors through contributions)

Relationships are through primary keys

Supported relationship types:

belongs_to (book belongs to author)

has_one (book has one publisher)

has_many (book has many pages)

has_and_belongs_to_many (book has and belongs to many readers)

has_many :through (book has many contributors through contributions)

ActiveRecord Validation validates_presence_of validates_uniqueness_of validates_confirmation_of validates_acceptance_of validates_associated validates_each validates_format_of, _length_of validates_exclusion_of, _inclusion_of

validates_presence_of

validates_uniqueness_of

validates_confirmation_of

validates_acceptance_of

validates_associated

validates_each

validates_format_of, _length_of

validates_exclusion_of, _inclusion_of

More ActiveRecord Acts As acts_as_list (position) acts_as_tree (parent_id) Aggregations composed_of Callbacks Full lifecycle Before and after validation, creation, saving, destroying Calculations average, count, maximum, minimum, sum

Acts As

acts_as_list (position)

acts_as_tree (parent_id)

Aggregations

composed_of

Callbacks

Full lifecycle

Before and after validation, creation, saving, destroying

Calculations

average, count, maximum, minimum, sum

Just When You Thought You Had Enough ActiveRecord Callback objects Observers Façade columns Object-level transaction management Magic column names created_on, created_at, updated_on, updated_at auto timestamping and dating lock_version and optimistic locking type for single table inheritence xxx_count counter cache

Callback objects

Observers

Façade columns

Object-level transaction management

Magic column names

created_on, created_at, updated_on, updated_at auto timestamping and dating

lock_version and optimistic locking

type for single table inheritence

xxx_count counter cache

Other Stuff ActionMailer for sending mail messages ActionView helpers Form helpers Asset tags Javascript support (yummy AJAX!) Pagination Text helpers ActionWebService Ruby language extensions Breakpoint and debugging

ActionMailer for sending mail messages

ActionView helpers

Form helpers

Asset tags

Javascript support (yummy AJAX!)

Pagination

Text helpers

ActionWebService

Ruby language extensions

Breakpoint and debugging

Where To Go Next? http://www.rubyonrails.com / http://api.rubyonrails.com / http://wiki.rubyonrails.com/ Agile Web Development with Rails http://www.ruby-doc.org/ for Ruby Programming Ruby IRC, Mailing Lists, Seth Ladd’s brain

http://www.rubyonrails.com /

http://api.rubyonrails.com /

http://wiki.rubyonrails.com/

Agile Web Development with Rails

http://www.ruby-doc.org/ for Ruby

Programming Ruby

IRC, Mailing Lists, Seth Ladd’s brain