nodeJS模块猫鼬给了我错误答案

【问题标题】：nodeJS module mongoose is giving me errorsnodeJS模块猫鼬给了我错误
【发布时间】：2015-10-26 07:33:00
【问题描述】：

当我运行我的代码时，我得到一个错误我想要做的是当有人登录到我的网站时，它会将 IP 和其他数据记录到数据库中。它似乎有效，但随后我收到此错误并退出我的应用程序

{ [Error: Trying to open unclosed connection.] state: 1 }
Connection to database has been established

/home/azura/node_modules/mongoose/lib/index.js:343
      throw new mongoose.Error.OverwriteModelError(name);
        ^
OverwriteModelError: Cannot overwrite `dataType` model once compiled.
    at Mongoose.model (/home/azura/node_modules/mongoose/lib/index.js:343:13)
at Namespace.<anonymous> (/home/azura/Desktop/dbWrite.js:19:37)
at Namespace.EventEmitter.emit (events.js:95:17)
at Namespace.emit (/home/azura/node_modules/socket.io/lib/namespace.js:205:10)
at /home/azura/node_modules/socket.io/lib/namespace.js:172:14
at process._tickCallback (node.js:415:13)

我使用的代码是：

var mongoose = require("mongoose");
var express = require("express");
var app = express();
var http = require("http").Server(app);
var io = require("socket.io")(http);
app.get("/", function (req, res) {
    res.sendFile(__dirname + "/index.html");
});
io.on("connection", function (socket) {
    var ip = socket.request.socket.remoteAddress;
    var dataBase = mongoose.connection;
    mongoose.connect("mongodb://localhost:27017/NEW_DB1");
    dataBase.on("error", console.error);
    console.log("Connection to database has been established");
    var collectedData = new mongoose.Schema({
        ipAddress: String,
        time: Number
    });
    var collectionOfData = mongoose.model("dataType", collectedData);
    var Maindata = new collectionOfData({
        ipAddress: ip,
        time: 100000000000000000
    });
    Maindata.save(function (err, Maindata) {
        if (err) {
            return console.error(err);
        } else {
            console.dir(Maindata);
        }
    });
});
http.listen(10203, function () {
    console.log("Server is up");
});

index.html 文件中没有任何重要内容。我只是想知道为什么我会收到这个错误。我该怎么做才能解决它？

【问题讨论】：

标签： javascript node.js mongodb mongoose database

【解决方案1】：

将此代码置于连接范围之外。无需为每种类型都创建 Schema 有新的连接事件。

mongoose.connect("mongodb://localhost:27017/NEW_DB1");
dataBase.on("error", console.error);
console.log("Connection to database has been established");
var collectedData = new mongoose.Schema({
    ipAddress: String,
    time: Number
});
var collectionOfData = mongoose.model("dataType", collectedData);




io.on("connection", function (socket) {
    var ip = socket.request.socket.remoteAddress;
    var dataBase = mongoose.connection;
    var Maindata = new collectionOfData({
        ipAddress: ip,
        time: 100000000000000000
    });
    Maindata.save(function (err, Maindata) {
        if (err) {
            return console.error(err);
        } else {
            console.dir(Maindata);
        }
    });
});

【讨论】：

【解决方案2】：

每次有连接进来，就会发出“连接”事件，所以 mongoose.connect("mongodb://localhost:27017/NEW_DB1"); 将执行多次，这会导致错误。

【讨论】：