在Postgres中使用Rails数组

Question

我有一个名为content的postgres列，它是一个数组。

但是当我试图以一种形式使用它时：

无法将ActionController :: Parameters转换为文本

尽管输出看起来很不错：

{"utf8"=>"✓",
 "_method"=>"patch",
 "authenticity_token"=>"NkK4BggxknfEn0A8shTs06xmesERaZdYtZdl9oEEUTk=",
 "notification_template"=>{"content"=>{"0"=>"Join us {{event_time}} {{{twitter_name}}} to win Big! hint: {{{question}}} #quiz {{location_tags}} {{url}} sdfsdfsdf"}},
 "commit"=>"Update Notification template",
 "id"=>"25"}

强大的参数

params.require(:notification_template).permit(:name, :content => {})

路由

resources :notification_templates do
  get 'edit/:id', to: 'notification_templates#edit_content', as: 'edit_content'
end

控制器

  def edit_content
    @notification_template = NotificationTemplate.find(params[:notification_template_id])
  end

  def update
    if @notification_template.update(notification_template_params)
      redirect_to admin_notification_template_path(@notification_template), notice: 'Social message was successfully updated.'
    else
      render action: 'edit'
    end
  end

我的表格

网址如下：/ notification_templates / 25 / edit_content / 7＃自定义操作，但使用正常更新

<%= simple_form_for([:admin, @notification_template]) do |f| %>
  <%= f.error_notification %>

  <div class="form-inputs">
    <%= f.simple_fields_for :content do |fields| %>
        <%= fields.input params[:id], input_html: { value: @notification_template.content[params[:id].to_i] } %>
    <% end %>
  </div>

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

<% end %>

数据库列

add_column :notification_templates, :content, :text, array: true, default: []

最后，我不确定添加它的惯例。以上工作正常，但我也注意到其他可能性，如

add_column :notification_templates, :content, :text, array: true, default: []
add_column :notification_templates, :content, :sting, array: true, default: []
add_column :notification_templates, :content, :text, array: true, default: {}

我选择第一个，因为字符串不允许尽可能多的字符，而且文本更方便。此外，默认为[]与{}或'{}'

但是在postgres中看到content text[] DEFAULT '{}'::text[]

登录

Started PATCH "/admin/notification_templates/25" for 127.0.0.1 at 2014-11-28 14:25:43 +0100
Processing by Admin::NotificationTemplatesController#update as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"NkK4BggxknfEn0A8shTs06xmesERaZdYtZdl9oEEUTk=", "notification_template"=>{"content"=>{"4"=>"{{{question}}} Study up and stop by {{{twitter_name}}} {{event_time}} for a #quiz {{location_tags}} {{url}} sdfsdfsdf"}}, "commit"=>"Update Notification template", "id"=>"25"}
  User Load (0.9ms)  SELECT  "users".* FROM "users"  WHERE "users"."id" = 1  ORDER BY "users"."id" ASC LIMIT 1
  NotificationTemplate Load (0.5ms)  SELECT  "notification_templates".* FROM "notification_templates"  WHERE "notification_templates"."id" = $1 LIMIT 1  [["id", 25]]
   (0.3ms)  BEGIN
   (0.3ms)  ROLLBACK
Completed 500 Internal Server Error in 54ms
Reporting exception: can't cast ActionController::Parameters to text

TypeError (can't cast ActionController::Parameters to text):
  app/controllers/admin/notification_templates_controller.rb:40:in `update'


  Rendered /Users/holden/.rvm/gems/ruby-2.0.0-p481@questionone-2.0/gems/actionpack-4.1.7/lib/action_dispatch/middleware/templates/rescues/_source.erb (1.1ms)
  Rendered /Users/holden/.rvm/gems/ruby-2.0.0-p481@questionone-2.0/gems/actionpack-4.1.7/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb (2.0ms)
  Rendered /Users/holden/.rvm/gems/ruby-2.0.0-p481@questionone-2.0/gems/actionpack-4.1.7/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb (1.4ms)
  Rendered /Users/holden/.rvm/gems/ruby-2.0.0-p481@questionone-2.0/gems/actionpack-4.1.7/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (27.5ms)

更新

我还观察到更新阵列类型字段在控制台中没有按预期工作。

例如。如果我尝试更新数组的成员，something = record.content[2] = 'blah'它似乎工作。但是当我保存记录时，它不会更新它。

Answer 1

是的，Rails postgres阵列仍然有点不稳定。 Hstore有点容易。

您可以通过虚拟属性更好地服务并明确地执行您想要的操作，而不是通过表单依赖标准的rails行为。

例如

def content_member=(member)
    unless member.blank?
        self.content_will_change!
        self.content[member.keys.first.to_i] = member.values.first
    end
end

如果你要更新数组的成员，你还需要让rails知道，这就是它在控制台中不起作用的原因。

这里有一个完整的解释：

Rails 4 Postgresql array data-type: updating values