关于Node.js的问题 SChema和模型

关于Node.js的问题 架构，模型和npm。 我是node.js的新手，并按照步骤在mongoose文档中创build模式和模型。

http://mongoosejs.com/docs/

我正在尝试使用kittens.js输出我在index.js中创build的模型，但我不确定是否正确。

有错误当我尝试编译时，

C:\Atom\initial\index.js:11 db.on('error', console.error.bind(console, 'connection_error')); ^ TypeError: Cannot read property 'on' of undefined at Object.<anonymous> (C:\Atom\initial\index.js:11:3) at Module._compile (module.js:570:32) at Object.Module._extensions..js (module.js:579:10) at Module.load (module.js:487:32) at tryModuleLoad (module.js:446:12) at Function.Module._load (module.js:438:3) at Module.runMain (module.js:604:10) at run (bootstrap_node.js:394:7) at startup (bootstrap_node.js:149:9) at bootstrap_node.js:509:3 

我在index.js中有以下代码。

  var express = require('express'); var mongoose = require('mongoose'); var path = require('path'); var logger = require('morgan'); var bodyParser = require('body-parser'); var Kitty = require('./models/kittens.js'); mongoose.connect("my database"); db.on('error', console.error.bind(console, 'connection_error')); db.once('open', function(){ console.log("Connected!"); }); var db = mongoose.connection; var Kitty = db.model('Kitty', kittySchema); var silence = new Kitty({name: 'Silence'}); console.log(silence.name); db.close(); 

这是我的模型模式。

  var mongoose = require('mongoose'); var Schema = mongoose.Schema; var kittySchema = new Schema({ name: String }); var Kitty = mongoose.model('Kitty', kittySchema); module.exports = Kitty; 

最初，我以为这是因为我没有安装npm express和mongoose，但是当我尝试安装它们时，有这样的错误信息

 [ ..............] \ fetchMetadata: verb afterAddevents.js:160ps://registry.npmjs.org/mime-types throw er; // Unhandled 'error' event ^ Error: This socket is closed at WriteStream.Socket._writeGeneric (net.js:678:19) at WriteStream.Socket._write (net.js:729:8) at doWrite (_stream_writable.js:333:12) at writeOrBuffer (_stream_writable.js:319:5) at WriteStream.Writable.write (_stream_writable.js:246:11) at WriteStream.Socket.write (net.js:656:40) at Object.Gauge._doRedraw (C:\Program Files\nodejs\node_modules\npm\node_modules\npmlog\node_mo dules\gauge\index.js:208:26) at Object.Gauge.hide (C:\Program Files\nodejs\node_modules\npm\node_modules\npmlog\node_modules \gauge\index.js:162:8) at EventEmitter.log.clearProgress (C:\Program Files\nodejs\node_modules\npm\node_modules\npmlog \log.js:127:14) at EventEmitter.log.disableProgress (C:\Program Files\nodejs\node_modules\npm\node_modules\npml og\log.js:88:8) 

当我试图在其他文件中安装express和mongoose时，也发生了这种情况。

任何想法帮助我！ 谢谢！

Answer 1

其实function是悬挂在顶部，所以首先你必须定义数据库variables，然后使用它。

  var express = require('express'); var mongoose = require('mongoose'); var path = require('path'); var logger = require('morgan'); var bodyParser = require('body-parser'); var Kitty = require('./models/kittens.js'); mongoose.connect("my database"); var db = mongoose.connection; db.on('error', console.error.bind(console, 'connection_error')); db.once('open', function(){ console.log("Connected!"); }); var Kitty = db.model('Kitty', kittySchema); var silence = new Kitty({name: 'Silence'}); console.log(silence.name); db.close();