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Migrations in Rails 2.1

Migrations in Rails 2.1
有跑過的migration, 會紀錄在schema_migrations 裡
強化了一些change column的功能
<br /># in a migration file<br />def self.up<br /> change_table :products do |t|<br /> t.rename :released_on, :released_at<br /> t.change :description, :text, :limit => nil, :null => true<br /> t.remove :price<br /> t.integer :stock_quantity<br /> end<br />end<br /><br />def self.down<br /> change_table :products do |t|<br /> t.rename :released_at, :released_on<br /> t.change :description, :string, :null => false<br /> t.decimal :price, :precision => 10, :scale => 2<br /> t.remove :stock_quantity<br /> end<br />end<br />

Non Active Record Model

Non Active Record Model
<br /><br /><br /># models/letter.rb<br />class Letter<br /> attr_reader :char<br /> <br /> def self.all<br /> ('A'..'Z').map { |c| new(c) }<br /> end<br /> <br /> def self.find(param)<br /> all.detect { |l| l.to_param == param } || raise(ActiveRecord::RecordNotFound)<br /> end<br /> <br /> def initialize(char)<br /> @char = char<br /> end<br /> <br /> def to_param<br /> @char.downcase<br /> end<br /> <br /> def products<br /> Product.find(:all, :conditions => ["name LIKE ?", @char + '%'], :order => "name")<br /> end<br />end<br /><br /># letters_controller.rb<br />def index<br /> @letters = Letter.all<br />end<br /><br />def show<br /> @letter = Letter.find(params[:id])<br />end<br /><br /><br /><br /><br /><!-- letters/index.html.erb --><br /><% title "Select a Letter" %><br /><br /><% for letter in @letters %><br /> <%= link_to letter.char, letter %><br /><% end %><br /><br /><!-- letters/show.html.erb --><br /><% title "Products for Letter #{@letter.char}" %><br /><br /><p><%= link_to "Select a Letter", letters_path %></p><br /><br /><%= render :partial => @letter.products %><br />

Going Back

<br /># cart_items_controller.rb<br />def create<br /> current_cart.cart_items.create!(params[:cart_item])<br /> flash[:notice] = "Product added to cart"<br /> redirect_to :back<br />end<br /><br /># or<br /><br />def create<br /> current_cart.cart_items.create!(params[:cart_item])<br /> flash[:notice] = "Product added to cart"<br /> session[:last_product_page] = request.env['HTTP_REFERER'] || products_url<br /> redirect_to current_cart_url<br />end<br /><br /><br /><!-- carts/show.html.erb --><br /><% if session[:last_product_page] %><br /> <%= link_to "Continue Shopping", session[:last_product_page] %> |<br /><% end %><br />

Helpers Outside Views

Helpers outside views
<br /># models/category.rb<br />def description<br /> "This category has #{helpers.pluralize(products.count, 'product')}."<br />end<br /><br />def helpers<br /> ActionController::Base.helpers<br />end<br /><br /># products_controller.rb<br />def create<br /> @product = Product.new(params[:product])<br /> if @product.save<br /> flash[:notice] = "Successfully created #{@template.link_to('product', @product)}."<br /> redirect_to products_url<br /> else<br /> render :action => 'new'<br /> end<br />end<br />

JSON

<br />>> ActiveSupport::JSON.decode("{\"name\":\"a\",\"id\":\"1\"}")<br />=> {"name"=>"a", "id"=>"1"}<br /><br />>> ActiveSupport::JSON.encode({"name"=>"a", "id"=>"1"})<br />=> "{\"name\": \"a\", \"id\": \"1\"}<br />這個encode, decode 是ruby 做的<br /><br />還有C的json encode, decode gem 可以裝<br />

javascript tips

<br /> <[ form name ="myform"]>.....<[/form]><br /> //可以直接指定 event trigger 的 function<br /> document.myform.onsubmit = validateform<br />