ruby-on-rails - 从 Ruby on Rails 应用程序中的模型访问数据

Question

在我的应用程序中，当前用户通过 index.html.erb

中的表单设置他的总体目标

现在我想将该值绑定(bind)到一个实例变量并在 View 中显示该实例变量。

我是 ruby​​ on rails 的新手，所以我不确定如何管理它。

我尝试了各种类型的代码来访问数据，但都没有成功。 谁能帮我解决这个问题？

例如:

@general_goal = Goal.find(params[:id])
general_goal = @general_goal.user.general_goal

给出了错误:Couldn't find Goal with 'id'= 和

@general_goal = Goal.find(params[:general_goal])

还给出错误:Couldn't find Goal with 'id'=

这是goals_controller.rb

class GoalsController < ApplicationController

  before_action :set_goal, only: [:edit, :update, :show, :destroy]
  #before_action :goal_owner, only: [ :edit, :update, :destroy]

  def new
    @goal = current_user.goals.build
  end

  def index
    @Newgeneralgoal = Goal.new

    @goals = current_user.goals.order(created_at: :desc).limit(5)   
  end

  def create 
    @goal = Goal.new(goal_params)
    @goal.user_id = current_user.id

    if (@goal.save)
      redirect_to transaction_path(current_user), :notice => "Goal has been saved successfully."
    else
      f.html { redirect_to "", notice: "Error: Goal Not created!!"}
    end 

  end

  def update
    if @goal.update(goal_params)
    flash[:success] = "Goal was successfully updated"
    redirect_to goals_path(@goal)
  else
    render 'edit'
  end       

  def destroy
    @goal.destroy
    flash[:danger] = "Goal was successfully destroyed"
    redirect_to goal_path(current_user) 
  end

  private

  def set_goal
    @goal = Goal.find(params[:id])
  end

  def goal_params
    params.require(:goal).permit(:user_id, :general_goal, :date)
  end
end

我可以通过以下方式访问 View 中的目标:

<% @goals.each do |goal| %>
  <tr>
    <td><%= goal.date.try(:strftime,"%Y/%m/%d")%></td>                      
    <td><%= goal.general_goal  %></td>
  </tr>
<% end %>

所以我基本上是在问，如果用户将一般目标设置为“5”，我如何从数据库中获取“5”并将其分配给变量？

这是目标的schema.rb

create_table "goals", force: :cascade do |t|
  t.datetime "date"
  t.decimal  "general_goal"
  t.integer  "user_id"
  t.datetime "created_at",     null: false
  t.datetime "updated_at",     null: false
end

这是 goal.rb 模型

class Goal < ActiveRecord::Base
  belongs_to :user
end

这里是user.rb模型

class User < ActiveRecord::Base
 # Include default devise modules. Others available are:
 # :confirmable, :lockable, :timeoutable and :omniauthable
 devise :database_authenticatable, :registerable,
     :recoverable, :rememberable, :trackable, :validatable

     has_many :goals

 end

Answer 1

如果我没理解错的话，你想为 current_user 显示 :general_goal 的值？

这可能对您有用，只需将这段代码放在 Controller 的 index 中。我还没有测试过它，但它可能会起作用。

current_general_goal = @current_user.goals.sum(:general_goal)     
@general_goal =  current_general_goal.nil? ? 0 : current_general_goal

它检查 :general_goal 是否为 nil，如果是则显示 0，否则显示一般目标值。

更新

如果您想要来自当前用户的最后一个 general_goal 的值。您可以将此代码添加到索引 View 中。

current_general_goal = @current_user.goals.last.general_goal
@general_goal =  (current_general_goal.nil? ? 0 : current_general_goal) 

请告诉我这是否适合你