如果实际数量变为零，则完全删除相应行

Question

如果 tquantity = 0 我想完全删除相应的行。

找到下面的屏幕截图以便更好地理解；

index.html.erb

<div class="col-md-10 col-md-offset-1">

        <div class="table-responsive myTable">

            <table class="table listing text-center">
                <tr class="tr-head">
                    <td>DESCRIPTION</td>
                    <td>COLOR</td>
                    <td>QUANTITY</td>
                    <td>RETAIL PRICE</td>
                    <td>TOTAL AMOUNT</td>
                    <td>CARTON NO</td>
                    <td>CUSTOMER 1</td>
                    <td>CUSTOMER 2</td>
                    <td>ACTUAL QUANTITY</td>
                </tr>

                <% @purchases.each do |purchase| %>

                <tr class="tr-<%= cycle('odd', 'even') %>">

                    <td class="col-2"><%= purchase.description %></td>
                    <td class="col-1"><%= purchase.color %></td>
                    <td class="col-2"><%= purchase.quantity %></td>
                    <td class="col-2"><%= number_with_precision(purchase.rprice, :delimiter => ",", :precision => 2) %></td>        
                    <td class="col-2"><%= number_with_precision(purchase.tamount, :delimiter => ",", :precision => 2) %></td>  
                    <td class="col-2"><%= purchase.cartonno %></td>
                    <td class="col-2"><%= purchase.cus1 %></td>
                    <td class="col-2"><%= purchase.cus2 %></td>
                    <td class="col-2"><%= tquantity = purchase.quantity - purchase.cus1 - purchase.cus2 %></td>

                </tr>

                <% end %>

            </table>

        </div>
    </div>
</div>

purchases_controller.rb

class PurchasesController < ApplicationController
        before_action :set_purchase, only: [:show, :edit, :update, :destroy]

  # GET /Stockings
  # GET /deldetails.json
  def index
    #@purchases = Purchase.all
    @purchases = Purchase.where("tquantity !=?", 0)
  end

  def import
    Purchase.import(params[:file])
    redirect_to purchases_url, notice: "Purchases imported."
  end

  # GET /purchases/1
  # GET /purchases/1.json
  def show
  end

  # GET /purchases/new
  def new
    @purchase = Purchase.new
  end

  # GET /purchases/1/edit
  def edit
  end

  # POST /purchases
  # POST /purchases.json
  def create
    @purchase = Purchase.new(purchase_params)

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

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

  # DELETE /purchases/1
  # DELETE /purchases/1.json
  def destroy
    @purchase.destroy
    respond_to do |format|
      format.html { redirect_to purchases_url, notice: 'Purchase was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

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

    # Never trust parameters from the scary internet, only allow the white list through.
    def purchase_params
      params.require(:purchase).permit(:season, :category, :articleno, :description, :color, :quantity, :rprice, :tamount, :cartonno, :cus1, :cus2, :tquantity )
    end
end

purchase.rb

class Purchase < ActiveRecord::Base

    def self.import(file)
        CSV.foreach(file.path, headers: true) do |row|
            Purchase.create! row.to_hash
        end
    end
end

我是否需要使用 SQL WHERE 子句，如果需要，我将如何获得所需的结果？

Answer 1

我遇到了类似的问题并使用 destroy_all 而不是 destroy 解决了这个问题。这清除了为我显示的行。让我知道是否有帮助。

Answer 2

在您的 update 操作中，您需要检查新值是否会导致购买符合您设置的删除条件。使用对 update 操作的这些更改来实现这一点：

# PATCH/PUT /purchases/1
# PATCH/PUT /purchases/1.json
def update
  respond_to do |format|
    updated = @purchase.update(purchase_params)
    deleted = (@purchase.quantity - @purchase.cus1 - @purchase.cus2) <= 0
    if deleted
      @purchase.destroy
      format.html { redirect_to purchases_url, notice: 'Purchase was deleted.' }
      format.json { head :no_content }
    elsif updated
      format.html { redirect_to @purchase, notice: 'Purchase was successfully updated.' }
      format.json { render :show, status: :ok, location: @purchase }
    else
      format.html { render :edit }
      format.json { render json: @purchase.errors, status: :unprocessable_entity }
    end
  end
end

关于视图，如果数据中恰好有需要过滤的行，可以使用这个查询：

# GET /Stockings
# GET /deldetails.json
def index
  @purchases = Purchase.where("quantity - cus1 - cus2 > 0") # Only records with a valid total quantity
end

对于 CSV 导入，可以在创建购买模型之前过滤值 object。尝试更改为使用此：

def self.import(file)
  CSV.foreach(file.path, headers: true) do |row|
    if (row["quantity"].to_i - row["cus1"].to_i - row["cus2"].to_i) > 0
      Purchase.create! row.to_hash
    end
  end
end

这将消除在 CSV 导入过程中在应用程序中创建的任何无效（零数量）采购模型 object。这假设 header 字段被命名为 "quantity"、"cus1" 和 "cus2"，并且可能需要稍微调整以匹配实际的 header 字段名称。

如果实际数量变为零，则完全删除相应行

Delete the respective row completely if acutal quantity goes to zero

ruby

activerecord

ruby-on-rails

erb

ruby-on-rails-4