rails generate model/resource/scaffold的区别

If you’re just learning Ruby on Rails, you may be confused as to when to generate individual models, resources or scaffolding, and what files are created by each command.

Say you want to generate a Test model with a name.  You could either generate the model individually, generate resources, or generate scaffolding, as follows:

rails g model Test name:text
 
rails g resource Test name:text
 
rails g scaffold Test name:text

What’s the difference between each of the above?

Entering rails g model Test name:text in your command line will generate the following:

(1) A model file test.rb in your  models directory:

class Test < ActiveRecord::Base
end

(2) A migration file timestamp_create_tests.rb in your db/migrate directory:

class CreateTests < ActiveRecord::Migration
  def change
    create_table :tests do |t|
      t.text :name
 
      t.timestamps
    end
  end
end

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Entering rails g resource Test name:text in your command line will generate the following:

(1) A model file test.rb in your  models directory:

class Test < ActiveRecord::Base
end

(2) A migration file timestamp_create_tests.rb  in your db/migrate directory:

class CreateTests < ActiveRecord::Migration
  def change
    create_table :tests do |t|
      t.text :name
 
      t.timestamps
    end
  end
end

(3) a tests_controller.rb file in your  controllers directory.  This controller will be an empty shell:

class TestsController < ApplicationController
end

 (4) resources :tests routes in your routes.rb file.

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Entering rails g scaffold Test name:text in your command line will generate the following:

(1) A model file test.rb in your  models directory:

class Test < ActiveRecord::Base
end

(2) A migration file timestamp_create_tests.rb in your db/migrate directory:

class CreateTests < ActiveRecord::Migration
  def change
    create_table :tests do |t|
      t.text :name
 
      t.timestamps
    end
  end
end

(3) A tests_controller.rb file in your  controllers directory.  When a scaffold is generated, seven public methods and two private methods will be added to your controller:

(4) resources :tests routes in your routes.rb file.

(5) Seven corresponding view files in your  views directory: (a) _form.html.erb, (b) edit.html.erb, (c) index.html.erb, (d) index.json.jbuilder, (e) new.html.erb, (f) show.html.erb and (g) show.json.jbuilder. Each view will contain html and embedded ruby.