rails CRUD practice

rails new {name}

1. 建立專案
   • $ rails new {project_name}
   • $ cd {project_name}

Book (CRUD)

2. 建立路徑

   • in routes.rb
     • resources :books

3. 建立 Controller

   • $ rails g controller Books

4. 建立 actions

5. 建立 templates

6. 建立 Model

   • $ rails g model Book title content:text price:integer
     • title:string
     • content:text
     • price:integer

7. 建立 _form

<%= form_for book do |f| %>
  書名
  <%= f.text_field :title %>
  內容
  <%= f.text_area :content %>
  價格
  <%= f.number_field :price %>
  <%= f.submit %>
<% end %>

8. 建立新增頁面 new.html.erb

<h1>新增一本書</h1>
<%= render 'form', book: @book %>

9. 建立 Controller 內的 action : index new create show edit delete

   • 驗證 app/models/book.rb

   validates :title, presence: true
   

   • 資料清洗 app/controllers/books_controllers.rb

   def book_params
     params.require(:book).permit(:title, :content, :price)
   end
   

   • 抽出尋找特定id的方法

   before_action :find_book, only: [:show, :edit, :update, :destroy]
   private
   def find_book
     @book = Book.find_by(id: params[:id])
     redirect_to books_path if @book.nil?
   end