发生错误是因为您已经定义了一个架构，然后又在定义该架构。通常，您应该做的是一次实例化架构，然后在需要它时让一个全局对象调用它。
例如：
user_model.js
var mongoose = require('mongoose');var Schema = mongoose.Schema;var userSchema = new Schema({ name:String, email:String, password:String, phone:Number, _enabled:Boolean});module.exports = mongoose.model('users', userSchema);check.js
var mongoose = require('mongoose');var User = require('./user_model.js');var db = mongoose.createConnection('localhost', 'event-db');db.on('error', console.error.bind(console, 'connection error:'));var a1= db.once('open',function(){ User.find({},{},function (err, users) { mongoose.connection.close(); console.log("Username supplied"+username); //doSomethingHere })});insert.js
var mongoose = require('mongoose');var User = require('./user_model.js');mongoose.connect('mongodb://localhost/event-db');var new_user = new User({ name:req.body.name , email: req.body.email , password: req.body.password , phone: req.body.phone , _enabled:false });new_user.save(function(err){ if(err) console.log(err); });
