Ruby on rails Rails-通过数据库查询加速我的项目索引操作

我注意到，随着我不断开发我的应用程序，创建了很多项目/列表，加载时间越来越长。我怀疑这是我在控制器中查询数据库的方式。视图使用erb执行@item.each do并检查@item.orders.any？并且只显示没有订单的项目。代码基本上必须遍历数据库中的每一项执行此检查，然后呈现结果，我怀疑这将是一场超过100项的噩梦

有没有更聪明的方法

这是一个简单的市场应用程序，买家和卖家可以在其中进行交易。卖家列出一个项目，它与其他项目一起显示在项目索引页面上。买家点击它，然后点击购买，这会将他们带到一个订单页面，然后他们可以与贝宝签出。收到PayPal IPN后，订单将提交到数据库

代码如下：

加载索引操作时从服务器日志中摘录 项目控制器

class ItemsController


没有包含该术语的项目。
项目





以前

---

谢谢你的时间

尝试使用

includes

加载关联

class ItemsController < ApplicationController

  def index
    if params[:search]
      @items = Item.search(params[:search]).includes(:orders).order("created_at DESC")
    else
      @items = Item.all.includes(:orders).order("created_at DESC")
    end
  end
end

class ItemsController

谢谢！这很有效。服务器日志不再显示每个项目查询并执行订单加载，而不是订单存在。平均加载时间减少了约25毫秒。@bloodrunner好极了！作为表示感谢的方式，如果你对答案感到满意，你能接受吗？

class ItemsController < ApplicationController
  before_action :set_item, only: [:show, :edit, :update, :destroy]
  before_action :authenticate_user!, except: [:index, :show]
  rescue_from ActiveRecord::RecordNotFound, with: :deny_access
  rescue_from ActionView::MissingTemplate, with: :template_not_found


  def garage
    @items = current_user.items
  end

  def show
    @item = Item.find(params[:id])
  end

  # GET /items
  # GET /items.json
  def index
    @items = Item.all
    if params[:search]
      @items = Item.search(params[:search]).order("created_at DESC")
    else
      @items = Item.all.order("created_at DESC")
    end
  end

  # GET /items/new
  def new
    @item = current_user.items.build
  end

  # GET /items/1/edit
  def edit
  end

  # POST /items
  # POST /items.json
  def create
    @item = current_user.items.build(item_params)
    @item.username = current_user.username

    respond_to do |format|
      if @item.save
        format.html { redirect_to @item, notice: 'Item was successfully created.' }
        format.json { render :show, status: :created, location: @item }
      else
        format.html { render :new }
        format.json { render json: @item.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /items/1
  # PATCH/PUT /items/1.json
  def update
    respond_to do |format|
      if @item.update(item_params)
        format.html { redirect_to @item, notice: 'Item was successfully updated.' }
        format.json { render :show, status: :ok, location: @item }
      else
        format.html { render :edit }
        format.json { render json: @item.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /items/1
  # DELETE /items/1.json
  def destroy
    @item.destroy
    respond_to do |format|
      format.html { redirect_to items_url, notice: 'Item was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  def favorite
    @item = Item.find(params[:id])
    type = params[:type]
    if type == "favorite"
      current_user.favorites << @item
      redirect_to :back

    elsif type == "unfavorite"
      current_user.favorites.delete(@item)
      redirect_to :back

    else
      redirect_to :back
    end
  end

  def favorites
    @items = current_user.favorites
  end

  def deny_access
    redirect_to :back
  rescue ActionController::RedirectBackError
    redirect_to root_path
  end

  def template_not_found
    redirect_to :back
  rescue ActionView::MissingTemplate
    redirect_to root_path
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_item
      @item = Item.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def item_params
      params.require(:item).permit(:title, :content, :filepicker_url, :price, :shipping_price, :paypal_email)
    end
end

<div class="row">
  <%= form_tag(items_path, :method => "get") do %>
    <div class="col-lg-6 col-lg-offset-3">
      <div class="input-group">
        <%= text_field_tag :search, params[:search], placeholder: "Search items...", class: "form-control" %>
        <div class="input-group-btn">
            <%= submit_tag "Search", :name => nil, class: "btn btn-default btn-block" %>
        </div>
      </div>
    </div>
  <% end %>
</div>
<br>

<% if @items.blank? %>
  <h4>There are no items containing the term <%= params[:search] %>.</h4>
<% end %>

<h1>Items</h1>
      <% @items.each do |item| %>
      <% if item.orders.any? %>
        <% else %>
          <div class="col-md-3">
              <%= link_to(filepicker_image_tag(item.filepicker_url.split(",").last, w: 200, h: 200, fit: 'crop'), item) %><br>
              <p class="bold"><%= item.title %><br></p>
              <p><%= link_to number_to_currency(item.price), item %></p>
              <p class="small"><%= time_ago_in_words(item.created_at) %> ago</p>
          </div> 
        <% end %>
      <% end %>
<br>

class ItemsController < ApplicationController

  def index
    if params[:search]
      @items = Item.search(params[:search]).includes(:orders).order("created_at DESC")
    else
      @items = Item.all.includes(:orders).order("created_at DESC")
    end
  end
end