0

我是 RoR 的新手。我正在尝试创建一个基本的 Web 应用程序，其中配置文件页面显示属于特定配置文件的项目列表。

到目前为止，我有：

rails generate scaffold Profile name:string
rails generate scaffold Item description:string
rake db:migrate

在配置文件模型中：has_many :items在项目模型中：belongs_to :profile

当我尝试创建新配置文件时，我收到错误：

undefined method `item' for #<Profile

配置文件控制器

class ProfilesController < ApplicationController
  # GET /profiles
  # GET /profiles.json
  def index
    @profiles = profile.all

    respond_to do |format|
      format.html # index.html.erb
      format.json { render json: @profiles }
    end
  end

  # GET /profiles/1
  # GET /profiles/1.json
  def show
    @profile = profile.find(params[:id])

    respond_to do |format|
      format.html # show.html.erb
      format.json { render json: @profile }
    end
  end

  # GET /profiles/new
  # GET /profiles/new.json
  def new
    @profile = profile.new

    respond_to do |format|
      format.html # new.html.erb
      format.json { render json: @profile }
    end
  end

  # GET /profiles/1/edit
  def edit
    @profile = profile.find(params[:id])
  end

  # POST /profiles
  # POST /profiles.json
  def create
    @profile = profile.new(params[:profile])

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

  # PUT /profiles/1
  # PUT /profiles/1.json
  def update
    @profile = profile.find(params[:id])

    respond_to do |format|
      if @profile.update_attributes(params[:profile])
        format.html { redirect_to @profile, notice: 'profile was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: "edit" }
        format.json { render json: @profile.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /profiles/1
  # DELETE /profiles/1.json
  def destroy
    @profile = profile.find(params[:id])
    @profile.destroy

    respond_to do |format|
      format.html { redirect_to profiles_url }
      format.json { head :no_content }
    end
  end
end

配置文件 index.html.erb

<h1>Listing profiles</h1>

<table>
  <tr>
    <th>Name</th>
    <th></th>
    <th></th>
    <th></th>
  </tr>

<% @profiles.each do |profile| %>
  <tr>
    <td><%= profile.name %></td>
    <td><%= link_to 'Show', profile %></td>
    <td><%= link_to 'Edit', edit_profile_path(profile) %></td>
    <td><%= link_to 'Destroy', profile, method: :delete, data: { confirm: 'Are you sure?' } %></td>
  </tr>
<% end %>
</table>

<br />

<%= link_to 'New profile', new_profile_path %>

个人资料_show.html.erb

<%= simple_form_for(@profile) do |f| %>
  <%= f.error_notification %>

  <div class="form-inputs">
    <%= f.input :name %>
  </div>

  <div class="form-inputs">
    <%= f.input :item %>
  </div>

  <div class="form-actions">
    <%= f.button :submit %>
  </div>
<% end %>

完整的错误跟踪：

activemodel (3.2.12) lib/active_model/attribute_methods.rb:407:in `method_missing'
activerecord (3.2.12) lib/active_record/attribute_methods.rb:149:in `method_missing'
actionpack (3.2.12) lib/action_view/helpers/form_helper.rb:1161:in `value_before_type_cast'
actionpack (3.2.12) lib/action_view/helpers/form_helper.rb:1149:in `value_before_type_cast'
actionpack (3.2.12) lib/action_view/helpers/form_helper.rb:1043:in `block in to_input_field_tag'
actionpack (3.2.12) lib/action_view/helpers/form_helper.rb:1043:in `fetch'
actionpack (3.2.12) lib/action_view/helpers/form_helper.rb:1043:in `to_input_field_tag'
actionpack (3.2.12) lib/action_view/helpers/form_helper.rb:692:in `text_field'
actionpack (3.2.12) lib/action_view/helpers/form_helper.rb:1284:in `text_field'
simple_form (2.1.0) lib/simple_form/inputs/string_input.rb:13:in `input'
simple_form (2.1.0) lib/simple_form/wrappers/many.rb:29:in `block in render'
simple_form (2.1.0) lib/simple_form/wrappers/many.rb:27:in `each'
simple_form (2.1.0) lib/simple_form/wrappers/many.rb:27:in `render'
simple_form (2.1.0) lib/simple_form/wrappers/many.rb:29:in `block in render'
simple_form (2.1.0) lib/simple_form/wrappers/many.rb:27:in `each'
simple_form (2.1.0) lib/simple_form/wrappers/many.rb:27:in `render'
simple_form (2.1.0) lib/simple_form/wrappers/root.rb:15:in `render'
simple_form (2.1.0) lib/simple_form/form_builder.rb:117:in `input'
app/views/profiles/_form.html.erb:9:in `block in _app_views_profiles__form_html_erb___911765346923063960_2183588380'
actionpack (3.2.12) lib/action_view/helpers/capture_helper.rb:40:in `block in capture'
actionpack (3.2.12) lib/action_view/helpers/capture_helper.rb:187:in `with_output_buffer'
actionpack (3.2.12) lib/action_view/helpers/capture_helper.rb:40:in `capture'
actionpack (3.2.12) lib/action_view/helpers/form_helper.rb:607:in `fields_for'
actionpack (3.2.12) lib/action_view/helpers/form_helper.rb:378:in `form_for'
simple_form (2.1.0) lib/simple_form/action_view_extensions/form_helper.rb:29:in `block in simple_form_for'
simple_form (2.1.0) lib/simple_form/action_view_extensions/form_helper.rb:48:in `with_simple_form_field_error_proc'
simple_form (2.1.0) lib/simple_form/action_view_extensions/form_helper.rb:28:in `simple_form_for'
app/views/profiles/_form.html.erb:1:in `_app_views_profiles__form_html_erb___911765346923063960_2183588380'
actionpack (3.2.12) lib/action_view/template.rb:145:in `block in render'
activesupport (3.2.12) lib/active_support/notifications.rb:125:in `instrument'
actionpack (3.2.12) lib/action_view/template.rb:143:in `render'
actionpack (3.2.12) lib/action_view/renderer/partial_renderer.rb:265:in `render_partial'
actionpack (3.2.12) lib/action_view/renderer/partial_renderer.rb:238:in `block in render'
actionpack (3.2.12) lib/action_view/renderer/abstract_renderer.rb:38:in `block in instrument'
activesupport (3.2.12) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.12) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.12) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.12) lib/action_view/renderer/abstract_renderer.rb:38:in `instrument'
actionpack (3.2.12) lib/action_view/renderer/partial_renderer.rb:237:in `render'
actionpack (3.2.12) lib/action_view/renderer/renderer.rb:41:in `render_partial'
actionpack (3.2.12) lib/action_view/helpers/rendering_helper.rb:27:in `render'
app/views/profiles/new.html.erb:3:in `_app_views_profiles_new_html_erb___3444063506780261827_2182112400'
actionpack (3.2.12) lib/action_view/template.rb:145:in `block in render'
activesupport (3.2.12) lib/active_support/notifications.rb:125:in `instrument'
actionpack (3.2.12) lib/action_view/template.rb:143:in `render'
actionpack (3.2.12) lib/action_view/renderer/template_renderer.rb:47:in `block (2 levels) in render_template'
actionpack (3.2.12) lib/action_view/renderer/abstract_renderer.rb:38:in `block in instrument'
activesupport (3.2.12) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.12) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.12) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.12) lib/action_view/renderer/abstract_renderer.rb:38:in `instrument'
actionpack (3.2.12) lib/action_view/renderer/template_renderer.rb:46:in `block in render_template'
actionpack (3.2.12) lib/action_view/renderer/template_renderer.rb:54:in `render_with_layout'
actionpack (3.2.12) lib/action_view/renderer/template_renderer.rb:45:in `render_template'
actionpack (3.2.12) lib/action_view/renderer/template_renderer.rb:18:in `render'
actionpack (3.2.12) lib/action_view/renderer/renderer.rb:36:in `render_template'
actionpack (3.2.12) lib/action_view/renderer/renderer.rb:17:in `render'
actionpack (3.2.12) lib/abstract_controller/rendering.rb:110:in `_render_template'
actionpack (3.2.12) lib/action_controller/metal/streaming.rb:225:in `_render_template'
actionpack (3.2.12) lib/abstract_controller/rendering.rb:103:in `render_to_body'
actionpack (3.2.12) lib/action_controller/metal/renderers.rb:28:in `render_to_body'
actionpack (3.2.12) lib/action_controller/metal/compatibility.rb:50:in `render_to_body'
actionpack (3.2.12) lib/abstract_controller/rendering.rb:88:in `render'
actionpack (3.2.12) lib/action_controller/metal/rendering.rb:16:in `render'
actionpack (3.2.12) lib/action_controller/metal/instrumentation.rb:40:in `block (2 levels) in render'
activesupport (3.2.12) lib/active_support/core_ext/benchmark.rb:5:in `block in ms'
/usr/local/rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/benchmark.rb:295:in `realtime'
activesupport (3.2.12) lib/active_support/core_ext/benchmark.rb:5:in `ms'
actionpack (3.2.12) lib/action_controller/metal/instrumentation.rb:40:in `block in render'
actionpack (3.2.12) lib/action_controller/metal/instrumentation.rb:83:in `cleanup_view_runtime'
activerecord (3.2.12) lib/active_record/railties/controller_runtime.rb:24:in `cleanup_view_runtime'
actionpack (3.2.12) lib/action_controller/metal/instrumentation.rb:39:in `render'
actionpack (3.2.12) lib/action_controller/metal/implicit_render.rb:10:in `default_render'
actionpack (3.2.12) lib/action_controller/metal/mime_responds.rb:196:in `respond_to'
app/controllers/profiles_controller.rb:29:in `new'
actionpack (3.2.12) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (3.2.12) lib/abstract_controller/base.rb:167:in `process_action'
actionpack (3.2.12) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (3.2.12) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.2.12) lib/active_support/callbacks.rb:414:in `_run__312850119216024862__process_action__607287929354052739__callbacks'
activesupport (3.2.12) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.12) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks'
activesupport (3.2.12) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.12) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.2.12) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (3.2.12) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.2.12) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.12) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.12) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.12) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.2.12) lib/action_controller/metal/params_wrapper.rb:207:in `process_action'
activerecord (3.2.12) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (3.2.12) lib/abstract_controller/base.rb:121:in `process'
actionpack (3.2.12) lib/abstract_controller/rendering.rb:45:in `process'
actionpack (3.2.12) lib/action_controller/metal.rb:203:in `dispatch'
actionpack (3.2.12) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.2.12) lib/action_controller/metal.rb:246:in `block in action'
actionpack (3.2.12) lib/action_dispatch/routing/route_set.rb:73:in `call'
actionpack (3.2.12) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'
actionpack (3.2.12) lib/action_dispatch/routing/route_set.rb:36:in `call'
journey (1.0.4) lib/journey/router.rb:68:in `block in call'
journey (1.0.4) lib/journey/router.rb:56:in `each'
journey (1.0.4) lib/journey/router.rb:56:in `call'
actionpack (3.2.12) lib/action_dispatch/routing/route_set.rb:601:in `call'
warden (1.2.1) lib/warden/manager.rb:35:in `block in call'
warden (1.2.1) lib/warden/manager.rb:34:in `catch'
warden (1.2.1) lib/warden/manager.rb:34:in `call'
actionpack (3.2.12) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
rack (1.4.5) lib/rack/etag.rb:23:in `call'
rack (1.4.5) lib/rack/conditionalget.rb:25:in `call'
actionpack (3.2.12) lib/action_dispatch/middleware/head.rb:14:in `call'
actionpack (3.2.12) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.2.12) lib/action_dispatch/middleware/flash.rb:242:in `call'
rack (1.4.5) lib/rack/session/abstract/id.rb:210:in `context'
rack (1.4.5) lib/rack/session/abstract/id.rb:205:in `call'
actionpack (3.2.12) lib/action_dispatch/middleware/cookies.rb:341:in `call'
activerecord (3.2.12) lib/active_record/query_cache.rb:64:in `call'
activerecord (3.2.12) lib/active_record/connection_adapters/abstract/connection_pool.rb:479:in `call'
actionpack (3.2.12) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
activesupport (3.2.12) lib/active_support/callbacks.rb:405:in `_run__1382692569756144731__call__1219384665416315194__callbacks'
activesupport (3.2.12) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.12) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
activesupport (3.2.12) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.12) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (3.2.12) lib/action_dispatch/middleware/reloader.rb:65:in `call'
actionpack (3.2.12) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
actionpack (3.2.12) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
actionpack (3.2.12) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
railties (3.2.12) lib/rails/rack/logger.rb:32:in `call_app'
railties (3.2.12) lib/rails/rack/logger.rb:16:in `block in call'
activesupport (3.2.12) lib/active_support/tagged_logging.rb:22:in `tagged'
railties (3.2.12) lib/rails/rack/logger.rb:16:in `call'
actionpack (3.2.12) lib/action_dispatch/middleware/request_id.rb:22:in `call'
rack (1.4.5) lib/rack/methodoverride.rb:21:in `call'
rack (1.4.5) lib/rack/runtime.rb:17:in `call'
activesupport (3.2.12) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.4.5) lib/rack/lock.rb:15:in `call'
actionpack (3.2.12) lib/action_dispatch/middleware/static.rb:62:in `call'
railties (3.2.12) lib/rails/engine.rb:479:in `call'
railties (3.2.12) lib/rails/application.rb:223:in `call'
rack (1.4.5) lib/rack/content_length.rb:14:in `call'
railties (3.2.12) lib/rails/rack/log_tailer.rb:17:in `call'
rack (1.4.5) lib/rack/handler/webrick.rb:59:in `service'
/usr/local/rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
/usr/local/rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
/usr/local/rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'
4

2 回答 2

1

为了has_many :items工作，你需要profile_id:integer在你的Item模型中有一个。

您可以通过执行以下命令来完成

rails g migration add_profile_id_to_items profile_id:integer
rake db:migrate

这应该创建关联所需的外键。

之后你应该能够做这样的事情

@profile = Profile.create name: "MyProfile"
@item = @profile.items.build description: "This is my awesome item"
@item.save

有多种方法可以为配置文件创建项目，但这是最直接的方法。然后要检索这些项目，你会做这样的事情

@profile = Profile.find(some_id)
@items = Item.where(profile_id: @profile.id).all

或者

@profile = Profile.find(some_id)
@items = @profile.items
于 2013-03-22T02:00:24.797 回答
0

First of all, your Profile object does not have 'item' field. Check your object's attributes by executing these commands:

rails console
Profile.connection
Profile

or visit your db/schema.rb file

You will see that there is no attribute :item in your object's hash.

You probably want to show the profile's items in your show.html.erb view. First though, you need to create an Item of the profile that it belongs to like so:

item = Item.new(description: "Test description", profile_id: 1)

Then you can do:

Profile.first.items

Second, you have an error in your controller. Object's class should be capitalized, so:

rails console
profile = profile.new(name: "Test profile")

will raise an error

undefined method `new' for nil:NilClass
于 2017-03-01T14:55:02.160 回答