Mongoid 和 Rails答案

【问题标题】：Mongoid and RailsMongoid 和 Rails
【发布时间】：2014-03-27 18:54:19
【问题描述】：

如何将数组数据存储在mongoDB 中，然后获取并打印？我在 ruby 中使用 mongoid gem：

tweet.rb

class Tweet    
    include Mongoid::Document        
    field :id, type: Integer        
    field :text, type: String        
end

我是这样存储在数据库中的：

Tweet.new(id: tweet.id, text: tweet.text)

这是正确的方法吗？如何从数据库中检索和显示？

Edit

命令行出现这个错误：

[2014-03-29 13:06:17] 错误请求行:\x00\x00\x00?]\x01\x00\x00\x00\x0 0\x00?\a\x00\x00\x00\x00\x00\x00admin.$cmd\x00\x00\x00\x00\x00????\x13\x00\x00\x 00\x10ismaster\x00\x01\x00\x00\x00\x00'. [2014-03-29 13:06:17] ERROR Errno::ECONNABORTED: An established connection was a borted by the software in your host machine. c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:396:i nwrite' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:396:i n <<' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:396:i n_write_data' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:368:i n send_body_string' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:249:i nsend_body' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:152:i n send_response' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpserver.rb:110:inrun' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/server.rb:191:in blo ck in start_thread' [2014-03-29 13:06:37] ERROR bad Request-Line:\x00\x00\x00?]\x01\x00\x00\x00\x0 0\x00?\a\x00\x00\x00\x00\x00\x00admin.$cmd\x00\x00\x00\x00\x00????\x13\x00\x00\x 00\x10ismaster\x00\x01\x00\x00\x00\x00'。 [2014-03-29 13:06:37] 错误 Errno::ECONNABORTED：已建立的连接是被主机中的软件终止。 c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:396:i n write' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:396:i n_write_data' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:368:i nsend_body_string' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:249:i n send_body' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:152:i nsend_response' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpserver.rb:110:in run' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/server.rb:191:inblo ck in start_thread' [2014-03-29 13:06:57] 错误请求行:\x00\x00\x00\x04^\x01\x00\x00\x00 \x00\x00?\a\x00\x00\x00\x00\x00\x00admin.$cmd\x00\x00\x00\x00\x00????\x13\x00\x0 0\x00\x10ismaster\x00\x01\x00\x00\x00\x00'. [2014-03-29 13:06:57] ERROR Errno::ECONNABORTED: An established connection was a borted by the software in your host machine. c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:396:i nwrite' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:396:i n <<' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:396:i n_write_data' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:368:i n send_body_string' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:249:i nsend_body' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:152:i n send_response' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpserver.rb:110:inrun' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/server.rb:191:in blo ck in start_thread' [2014-03-29 13:07:17] ERROR bad Request-Line:\x00\x00\x00\x1D^\x01\x00\x00\x00 \x00\x00?\a\x00\x00\x00\x00\x00\x00admin.$cmd\x00\x00\x00\x00\x00????\x13\x00\x0 0\x00\x10是主控\x00\x01\x00\x00\x00\x00'。 [2014-03-29 13:07:17] 错误 Errno::ECONNABORTED：已建立的连接是被主机中的软件终止。 c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:396:i n write' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:396:i n_write_data' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:368:i nsend_body_string' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:249:i n send_body' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:152:i nsend_response' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpserver.rb:110:in run' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/server.rb:191:inblo ck in start_thread' [2014-03-29 13:07:37] 错误请求行:\x00\x00\x006^\x01\x00\x00\x00\x0 0\x00?\a\x00\x00\x00\x00\x00\x00admin.$cmd\x00\x00\x00\x00\x00????\x13\x00\x00\x 00\x10ismaster\x00\x01\x00\x00\x00\x00'. [2014-03-29 13:07:37] ERROR Errno::ECONNABORTED: An established connection was a borted by the software in your host machine. c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:396:i nwrite' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:396:i n <<' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:396:i n_write_data' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:368:i n send_body_string' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:249:i nsend_body' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:152:i n send_response' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpserver.rb:110:inrun' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/server.rb:191:in blo ck in start_thread' [2014-03-29 13:07:57] ERROR bad Request-Line:\x00\x00\x00O^\x01\x00\x00\x00\x0 0\x00?\a\x00\x00\x00\x00\x00\x00admin.$cmd\x00\x00\x00\x00\x00????\x13\x00\x00\x 00\x10ismaster\x00\x01\x00\x00\x00\x00'。 [2014-03-29 13:07:57] 错误 Errno::ECONNABORTED：已建立的连接是被主机中的软件终止。 c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:396:i n write' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:396:i n_write_data' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:368:i nsend_body_string' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:249:i n send_body' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpresponse.rb:152:i nsend_response' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpserver.rb:110:in run' c:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/server.rb:191:inblo ck in start_thread'

【问题讨论】：

标签： ruby-on-rails mongodb mongoid

【解决方案1】：

你很接近。

您不能在模型上声明“id”字段；当您包含 Mongoid::Document 时会发生这种情况。

此外，调用#new 将在您的应用程序中创建对象，但不会将其写入数据库。你的代码应该是这样的：

tweet.rb

class Tweet
  include Mongoid::Document
  field :text, type: String
end

创建一条新推文：

tweet = Tweet.new(text: "Ipsum Lorem") # This does not write to the database
tweet.save # This writes the tweet to the database

检索推文：

tweet = Tweet.find_by(text: "Ipsum Lorem")

保存推文：

tweet = Tweet.find_by(text: "Ipsum Lorem")
tweet.text = "New text!"
tweet.save
# OR
Tweet.find_by(text: "Ipsum Lorem").update_attribute(:text, "Some new text")

Mongoid 非常灵活。有许多方法可以从数据库中保存和检索信息。我建议你仔细阅读the mongoid docs here。

编辑：如果您需要 id 字段顺序，there's a gem for that.

【讨论】：

显示错误提示：无法连接到副本集的主节点#<:cluster:44002572 resolved_address="nil">]>
好的..这意味着您的数据库正在发生一些时髦的事情。如果您还没有，请运行命令“rails g mongoid:install”。另外，请确保您的数据库正在运行。通常“rails s”命令会解决这个问题，但由于您没有使用 ActiveRecord，因此您需要确保您的 mongodb 在启动服务器之前已经在运行。