Javascript 在模型''；编译过一次（或者我监督过一些事情）

你能帮我吗？我看不出这里出了什么问题

以下是server.js中的代码片段：

var mongoose = require('mongoose');

var MongoClient = require('mongodb').MongoClient
  , assert = require('assert');
var db = 'nodebook';
var url = ''
mongoose.createConnection('mongodb://localhost/'+db);

// The User
   var User = mongoose.model('User', {
     username: String,
     password: String,
     biography: String,
     image: String,
   });

每次“noding”server.js时都会出现此消息。 顺便说一句，我是node.js/mongoose的新手

来自终端的错误：

/Users/davidnoldner/node_modules/mongoose/lib/index.js:360
      throw new mongoose.Error.OverwriteModelError(name);
      ^
OverwriteModelError: Cannot overwrite `User` model once compiled.
    at Mongoose.model (/Users/davidnoldner/node_modules/mongoose/lib/index.js:360:13)
    at Server.<anonymous> (/Users/davidnoldner/Librament/server.js:46:21)
    at emitTwo (events.js:87:13)
    at Server.emit (events.js:172:7)
    at HTTPParser.parserOnIncoming [as onIncoming] (_http_server.js:533:12)
    at HTTPParser.parserOnHeadersComplete (_http_common.js:103:23)

---

谢谢

初始化mongoose模型时出错，没有遵循正确的语法和文档。参考链接中的mongoose文档

---

好的，我改变了它，并尝试了它与下一个模型以及，但我仍然收到相同的错误。代码现在看起来是这样的：const Schema=mongoose.Schema；//用户var User=mongoose.model（'User'，新模式（{username:String，password:String，传记：String，image:String，}））；var Status=mongoose.model（'Status'，新模式（{body:String，time:Number，username:String，image:String，comments:Array，likes:Array}））；默认情况下，MongoDb在端口

27017

上运行，在尝试建立连接时也指定端口号但没有任何更改。同样的问题。更新：我试图在这里找到解决方案：但是我没有用答案解决问题，这就是为什么我在这里打开了这个帖子。我的问题只基于一个名为server.js的文件，而我发现的其他类似问题则基于更多的文件，即关系中的insert.js和app.js。

2016-09-15T08:32:07.973+0200 W NETWORK  [HostnameCanonicalizationWorker] Failed to obtain name info for: [ (2620:9b::5dd:4570, "nodename nor servname provided, or not known"), (2620:9b::5dd:4570, "nodename nor servname provided, or not known"), (192.168.0.16, "nodename nor servname provided, or not known"), (5.221.69.112, "nodename nor servname provided, or not known"), (192.168.0.16, "nodename nor servname provided, or not known"), (5.221.69.112, "nodename nor servname provided, or not known") ]

var mongoose = require('mongoose');

var MongoClient = require('mongodb').MongoClient
   ,assert = require('assert');
var db = 'nodebook';
var url = ''
mongoose.createConnection('mongodb://localhost:27017/'+db);

const Schema = mongoose.Schema;
// The User
var User = mongoose.model('User', new Schema({
    username: String,
    password: String,
    biography: String,
    image: String,
}));