从 has_many 更改为 has_one 关系 rails

Question

这里是 personaldetails belongs_to 用户，给定的关系是 has_many，wrong.I 想要将 has_many 关系转换为 has_one 关系，即用户 has_one 个人资料。当我直接更改关系时，出现错误“未初始化常量 User::Personaldetails。请指导我如何转换关系。

Personaldetail.rb

class Personaldetail < ApplicationRecord
    belongs_to :user
end

User.rb

class User < ApplicationRecord
 has_many :personaldetails, dependent: :destroy
accepts_nested_attributes_for :personaldetails, reject_if: :all_blank, allow_destroy: true
end

routes.rb

 resources :users, except: [:new] do
  resources :personaldetails
 end

user_steps_controller.rb

class UserStepsController < ApplicationController
    include Wicked::Wizard
    steps : :personaldetails
    def show
        @user = current_user
        @personaldetails = @user.personaldetails.build
        render_wizard
    end

def update
    @user = current_user
    @user.update!(user_params)
    render_wizard @user
end
   
private

def user_params
    params.require(:user).permit(:name, :password, :password_confirmation, :user_id,
      personaldetails_attributes: [:id,:first_name, :last_name, :gmail, :mobile_no, :city, :state, :pin_code, :_destroy])
end
end

personaldetails.html.erb

<%= form_with(model: @user, url: wizard_path, local: true) do |form| %> 
  <%= form.fields_for :personaldetail,Personaldetail.new do |info| %>
    <%= render 'personaldetails_field', form: info %>
  <% end %>
  <%= form.submit %>
<% end %>

_personaldetails_field.html.erb

<div class="field">
<%= form.label :First_name %><br />
<%= form.text_field :first_name %>
</div>
<div class="field">
<%= form.label :Last_name %><br />
<%= form.text_field :last_name %>
</div>
<div class="field">
<%= form.label :email %><br />
<%= form.text_field :gmail %>
</div>
<div class="field">
<%= form.label :Mobile_number %><br />
<%= form.text_field :mobile_no %>
</div>
<div class="field">
<%= form.label :City %><br />
<%= form.text_field :city %>
</div>
<div class="field">
<%= form.label :State %><br />
<%= form.text_field :state %>
</div>
<div class="field">
<%= form.label :Pincode %><br />
<%= form.text_field :pin_code %>
</div>

所以解决方案是：

Personaldetail.rb

class Personaldetail < ApplicationRecord
    belongs_to :user
end

User.rb

class User < ApplicationRecord
 has_one :personaldetails, dependent: :destroy
accepts_nested_attributes_for :personaldetails, reject_if: :all_blank, allow_destroy: true
end

routes.rb

 resources :users, except: [:new] do
  resources :personaldetail
 end

user_steps_controller.rb

class UserStepsController < ApplicationController
    include Wicked::Wizard
    steps : :personaldetails
    def show
        @user = current_user
        render_wizard
    end

def update
    @user = current_user
    @user.update!(user_params)
    render_wizard @user
end
   
private

def user_params
    params.require(:user).permit(:name, :password, :password_confirmation, :user_id,
      personaldetails_attributes: [:id,:first_name, :last_name, :gmail, :mobile_no, :city, :state, :pin_code, :_destroy])
end
end

personaldetail.html.erb

<%= form_with(model: @user, url: wizard_path, local: true) do |form| %> 
  <%= form.fields_for :personaldetail,@user.personaldetail || @user.build_personaldetail do |info| %>
    <%= render 'personaldetail_field', form: info %>
  <% end %>
  <%= form.submit %>
<% end %>

_personaldetail_field.html.erb

<div class="field">
<%= form.label :First_name %><br />
<%= form.text_field :first_name %>
</div>
<div class="field">
<%= form.label :Last_name %><br />
<%= form.text_field :last_name %>
</div>
<div class="field">
<%= form.label :email %><br />
<%= form.text_field :gmail %>
</div>
<div class="field">
<%= form.label :Mobile_number %><br />
<%= form.text_field :mobile_no %>
</div>
<div class="field">
<%= form.label :City %><br />
<%= form.text_field :city %>
</div>
<div class="field">
<%= form.label :State %><br />
<%= form.text_field :state %>
</div>
<div class="field">
<%= form.label :Pincode %><br />
<%= form.text_field :pin_code %>
</div>

Answer 1

尝试：has_one :personaldetail, dependent: :destroy Rails 正在根据名称和关联类型猜测 class 名称，因此对于 has_many 他们将尝试单数化关联名称（personaldetails => Personaldetail）但对于 has_one 他们将尝试按原样到达它 (personaldetails => Personaldetails)

Answer 2

如 spickermann 的评论所述，has_many 关系需要复数形式，has_one 需要单数形式。也就是说，你应该已经可以从中推断出关系了：

@user.personaldetails # user has many personal details
@user.personaldetail  # user has one personal detail

只是一个考虑：当 objects/models 没有正确命名时会出现许多奇怪的情况。根据经验，您应该为需要命名的对象使用最合适和最准确的英语名词。在这种情况下，这将对您有很大帮助。在普通英语中，说“用户有个人详细信息”有些奇怪，但您当然会说“有个人详细信息”。特别是涉及到 ActiveRecord 关联时，Rails 语法应该尽可能接近英语，以避免以后的误解。我想如果模型不是“PersonalDetail”，而是称为“Account”或“Profile”，就不会出现这种混淆。

Answer 3

很少suggestions/comments

将模型名称保持为 PersonalDetail 而不是 Personaldetail 和关联名称 has_one :personal_detail
使用 has_one 关系，您可以使用 user.build_personal_detail.save
当您再次运行第二步时，它将在 personal_details table 中创建另一条记录，并且在该事务中它将 return 新记录。但是，之后当您尝试查询时，它将 return 第一个创建的 personal_details 记录而不是新记录。这是因为 ActiveRecord 默认按 id 排序，has_one 关系

从 has_many 更改为 has_one 关系 rails

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