Rails – Quick Setup

Step 1

rails new <appname>

This rails command takes as an argument the name of the project. It will create a subdirectory called app in the current working directory. The standard database preconfigured is SQLite. If you wish to configure other databases such as mysql, oracle, postgresql, sqlite2, sqlite3, pass the -d or –database=option to the command above.

Step 2 

rake db:create 

or

rake db:create:all (this will create test and production databases)

You can get rails to create a new database for you by running the rails command above. If you are using SQLite, the database will be automatically created for you.

Step 3 (Optional)

rails dbconsole

This will allow you to look into the tables and records created for your application.

Step 4 (Optional)

rake db:migrate

This will check if your application is connected to a database. You will see an error below if you did not configure the root’s password properly.

rake aborted!

Access denied for user ‘root’@’localhost’ (using password: NO) 

Step 5

rails generate model ModelName title:string body:text published_at:datetime

This command will create a model for the database. The model names in Rails corresponded to database table names. Article (model, camel-cased singular) => articles (table, lower-cased plural). Rails has a complex pluralization rules coded into it. So Person will create a table named people. You may pass in –skip -migration if you do not want to create a migration file. This command will create 4 files.

db/migrate/20140406203049_create_articles.rb

app/models/article.rb

test/unit/article_test.rb

test/fixtures/articles.yml

Step 6 

rake db:migrate 

If you are not planning to create tables manually through SQL, you can work with the migration file instead. After editing the migration file, run the rails command above.

Step 7 (Optional)

rake db:rollback

If you want to roll back the migration for any reason, run the rails command above. Due to the change instance method, it is easy for us to migrate-rollback database configurations.

Step 8

rails generate controller articles

This will create six files.

app/controllers/articles_controller.rb – handle requests and responses for the model Article

test/controllers/articles_controller_test.rb – functional tests for articles controller

app/helpers/articles_helper.rb – add utility methods used in views

test/helpers/articles_helper_test.rb – all helper tests for helper class

app/assets/javascript/articles.js.coffee – Javascript associated with views

app/assets/stylesheets/articles.css.scss – CSS specific to articles views

Step 9 

rails generate migration add_excerpt_and_location_to_articles excerpt:string location:string

If you wish to add more fields, you should do using migrations. Run the rails command above. The migration file appear like the code below.

class AddExcerptAndLocationToArticles < ActiveRecord::Migration

def change

#add_column method

#first argument is table name (articles)

#second argument is field name

#third argument is field type

add_column :articles, :excerpt, :string

add_column :article, :location, :string

end

end

#run rake db:migrate

Step 10

The rules for data integrity are the responsibility of the model (app/models/article.rb)

class Article < ActiveRecord::Base

validates_presence_of :title, :body

end