Ruby on rails 为什么我的控制器在新建后调用更新而不是创建

当我进入

new\u heuristic\u variant\u cycle\u path

时，我的应用程序会显示cycle的新视图，但表单上的提交按钮会显示“Update cycle”而不是“Create cycle”，当您单击提交按钮时，控制器会查找更新操作。为什么?

我有

/config/routes.rb:

Testivate::Application.routes.draw do
  resources :heuristics do
    resources :variants do
      resources :cycles
    end
  end
end

class Heuristic < ActiveRecord::Base
  has_many :variants
  has_many :cycles, :through => :variants
end

class Variant < ActiveRecord::Base
  belongs_to :heuristic
  has_many :cycles
end

class Cycle < ActiveRecord::Base
  belongs_to :variant
end

%h1 New Cycle
= render 'form'

= simple_form_for [@heuristic, @variant, @cycle] do |f|
  = f.button :submit

class CyclesController < ApplicationController
  def new
    @heuristic = Heuristic.find(params[:heuristic_id])
    @variant = @heuristic.variants.find(params[:variant_id])
    @cycle = @variant.cycles.create
    respond_to do |format|
      format.html # new.html.erb
    end
  end
  def create
    @heuristic = Heuristic.find(params[:heuristic_id])
    @variant = @heuristic.variants.find(params[:variant_id])
    @cycle = @variant.cycles.create(params[:cycle])
    respond_to do |format|
      if @cycle.save
        format.html { redirect_to heuristic_variant_cycles_path(@heuristic, @variant, @cycle), notice: 'Cycle was successfully created.' }
      else
        format.html { render action: "new" }
      end
    end
  end
end

/app/models/heuristics.rb:

Testivate::Application.routes.draw do
  resources :heuristics do
    resources :variants do
      resources :cycles
    end
  end
end

class Heuristic < ActiveRecord::Base
  has_many :variants
  has_many :cycles, :through => :variants
end

class Variant < ActiveRecord::Base
  belongs_to :heuristic
  has_many :cycles
end

class Cycle < ActiveRecord::Base
  belongs_to :variant
end

%h1 New Cycle
= render 'form'

= simple_form_for [@heuristic, @variant, @cycle] do |f|
  = f.button :submit

class CyclesController < ApplicationController
  def new
    @heuristic = Heuristic.find(params[:heuristic_id])
    @variant = @heuristic.variants.find(params[:variant_id])
    @cycle = @variant.cycles.create
    respond_to do |format|
      format.html # new.html.erb
    end
  end
  def create
    @heuristic = Heuristic.find(params[:heuristic_id])
    @variant = @heuristic.variants.find(params[:variant_id])
    @cycle = @variant.cycles.create(params[:cycle])
    respond_to do |format|
      if @cycle.save
        format.html { redirect_to heuristic_variant_cycles_path(@heuristic, @variant, @cycle), notice: 'Cycle was successfully created.' }
      else
        format.html { render action: "new" }
      end
    end
  end
end

/app/views/cycles/_-form.html.haml:

Testivate::Application.routes.draw do
  resources :heuristics do
    resources :variants do
      resources :cycles
    end
  end
end

class Heuristic < ActiveRecord::Base
  has_many :variants
  has_many :cycles, :through => :variants
end

class Variant < ActiveRecord::Base
  belongs_to :heuristic
  has_many :cycles
end

class Cycle < ActiveRecord::Base
  belongs_to :variant
end

%h1 New Cycle
= render 'form'

= simple_form_for [@heuristic, @variant, @cycle] do |f|
  = f.button :submit

class CyclesController < ApplicationController
  def new
    @heuristic = Heuristic.find(params[:heuristic_id])
    @variant = @heuristic.variants.find(params[:variant_id])
    @cycle = @variant.cycles.create
    respond_to do |format|
      format.html # new.html.erb
    end
  end
  def create
    @heuristic = Heuristic.find(params[:heuristic_id])
    @variant = @heuristic.variants.find(params[:variant_id])
    @cycle = @variant.cycles.create(params[:cycle])
    respond_to do |format|
      if @cycle.save
        format.html { redirect_to heuristic_variant_cycles_path(@heuristic, @variant, @cycle), notice: 'Cycle was successfully created.' }
      else
        format.html { render action: "new" }
      end
    end
  end
end

/app/controllers/cycles\u controller.rb:

Testivate::Application.routes.draw do
  resources :heuristics do
    resources :variants do
      resources :cycles
    end
  end
end

class Heuristic < ActiveRecord::Base
  has_many :variants
  has_many :cycles, :through => :variants
end

class Variant < ActiveRecord::Base
  belongs_to :heuristic
  has_many :cycles
end

class Cycle < ActiveRecord::Base
  belongs_to :variant
end

%h1 New Cycle
= render 'form'

= simple_form_for [@heuristic, @variant, @cycle] do |f|
  = f.button :submit

class CyclesController < ApplicationController
  def new
    @heuristic = Heuristic.find(params[:heuristic_id])
    @variant = @heuristic.variants.find(params[:variant_id])
    @cycle = @variant.cycles.create
    respond_to do |format|
      format.html # new.html.erb
    end
  end
  def create
    @heuristic = Heuristic.find(params[:heuristic_id])
    @variant = @heuristic.variants.find(params[:variant_id])
    @cycle = @variant.cycles.create(params[:cycle])
    respond_to do |format|
      if @cycle.save
        format.html { redirect_to heuristic_variant_cycles_path(@heuristic, @variant, @cycle), notice: 'Cycle was successfully created.' }
      else
        format.html { render action: "new" }
      end
    end
  end
end

类循环控制器

在控制器中，这行代码错误：

@cycle = @variant.cycles.create

应该是这样的：

@cycle = @variant.cycles.build

调用

create

时，记录将被保存。在文件中：

collection.build（attributes={}，…）

返回集合类型的一个或多个新对象，这些对象已使用属性实例化并通过外键链接到此对象，但尚未保存

create（attributes={}）

返回集合类型的新对象，该对象已使用属性实例化，通过外键链接到此对象，并且已保存（如果已通过验证）。注意：这仅在数据库中已存在基本模型时有效，而不是在新记录（未保存）时有效