SQLite3::SQLException: 没有这样的表: 消息: SELECT "messages".* FROM "messages"; [英] SQLite3::SQLException: no such table: messages: SELECT "messages".* FROM "messages"

问题描述

我正在制作一个基于 在这个 railscast 上的简单聊天应用程序.我发布了另一个关于此的问题，但我愚蠢地没有添加模型，然后我错误地命名了它.

I am making a simple chat app based on this railscast. I posted another question about this, but I stupidly did not add a model, and then I named it incorrectly.

不过，现在已经解决了.问题是，我什至不确定我是否需要一个数据库.我本来打算完成这个，然后把它上传到 heroku 上玩.我不想存储消息，但如果有必要，我会.这是我的代码.

However, that is now fixed. The thing is, I am not even sure if I need a database at all. I was originally going to finish this, then upload it on heroku to just play around with. I don't want to store the messages, but if it is necessary then I will. Here is my code.

index.html.erb

index.html.erb

<h1>Hack Chat</h1>

<ul id="chat">
  <%= render @messages %>
</ul>

<%= form_for Message.new, remote: true do |f| %>
  <%= f.text_field :content %>
  <%= f.submit "Send" %>
<% end %>

<%= subscribe_to "/messages/new" %>

控制器；

class MessagesController < ApplicationController

    def index
      @messages = Message.all
    end

    def create
        @message = Message.create!(params[:message])
        PrivatePub.publish_to("/messages/new", "alert('#{@message.content}');")
    end

end

模型；

class Message < ActiveRecord::Base
end

路线；

Hackchat::Application.routes.draw do
  root to: 'messages#index'
  resources :messages
end

宝石文件；

source 'https://rubygems.org'


gem 'rails', '4.0.0'

gem "rake", "~> 10.1.1"


gem 'sqlite3'

group :assets do 
  gem 'sass-rails', '~> 4.0.0'
  gem 'uglifier', '>= 1.3.0'
  gem 'coffee-rails', '~> 4.0.0'
end

gem 'jquery-rails'
gem 'private_pub'
gem "thin", "~> 1.6.1"

我运行了 bundle exec rake db:create, bundle exec rake db:migrate 但我仍然得到错误；

I ran bundle exec rake db:create, bundle exec rake db:migrate and I still get the error;

ActionView::Template::Error (SQLite3::SQLException: no such table: messages: SELECT "messages".* FROM "messages"):
    1: <h1>Hack Chat</h1>
    2: 
    3: <ul id="chat">
    4:   <%= render @messages %>
    5: </ul>
    6: 
    7: <%= form_for Message.new, remote: true do |f| %>
  app/views/messages/index.html.erb:4:in `_app_views_messages_index_html_erb__3441634471849115078_70351149151260'

任何和所有帮助将不胜感激.

Any and all help would be greatly appreciated.

推荐答案

@messages = Message.all

告诉 Rails 应用程序查询数据库以获取消息表中的每条消息.所以如果你想使用一个以这种方式使用 Rails 应用程序，那么是的，您必须拥有某种 messages 表.您说您不打算存储消息，因此 index 操作应该转到空白聊天屏幕.所以只要去掉@messages = Message.all.如果你想要一个滚动的聊天消息列表，我想你可以将每一行写入一个数组并让索引页面显示出来.只需在聊天会话开始时将该数组设置为空白即可.

Tells the Rails app to query the db for every message in the message table. So if you want to use a Rails app in that way, then yes you would have to have some sort of a messages table. You said you are not looking to store the messages so the index action should go to a blank chat screen. So just get rid of @messages = Message.all. If you wanted to have a scrolling list of chat messages I guess you could just write each line to an array and have the index page show that. Just set that array to be blank at the beginning of a chat session.

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