Javascript 如何使用node.js从mongodb获取数据

我试图在node.js中使用此代码从mongoDB获取数据，但它不起作用，甚至没有显示任何错误或结果。我已经测试了DB，有很多数据可用，比如[数据库输出]

    {
    "_id" : ObjectId("597321311e13c57335727a6d"),
    "name" : "Amanda",
    "publisher" : "MTV india"
    }
    {
    "_id" : ObjectId("5973220b1e13c57335727a6e"),
    "name" : "Deepka",
    "publisher" : "MTV"
    }
    {
    "_id" : ObjectId("597322141e13c57335727a6f"),
    "name" : "sunil",
    "publisher" : "MTV india"
    }

app.js

var express = require('express');
var app = express();
var MongoClient = require('mongodb').MongoClient;
var mongoose = require('mongoose');
var booksDetail = require('./modal/book');
var url = "mongodb://localhost:27017/example";

// Connect to the db
MongoClient.connect(url);


app.get('/api/books', function(req,res) {
    res.send("on book  page");
    booksDetail.find({})
    .exec(function(err, books) {
        console.log("--working--");
      if(err) {
        res.send('error occured')
        res.send('error occured')
      } else {
        console.log(books);
        res.json(books);
      }
    });

});

app.get('/api/school', function(req,res){
    res.send('hello this is school page');
});

app.listen(7900);
console.log('server is runing 7900')

modal/book.js

var mongoose = require('mongoose');
var Schema = mongoose.Schema;

var bookSchema = new Schema({
        name: {
            type: String,
            requierd: true
        },
        publisher : {
            type: String,
            requierd: true
        }   
})

module.exports = mongoose.model('booksDetail', bookSchema);

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您尚未连接到MongoDB服务器（使用mongoose）

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选择使用mongoose或mongodb库，而不是两者都使用。仔细检查文档。

您加载mongo和mongoose，但使用mongo进行连接，并且您的文档存储在mongoose中。所以只需移除mongo并连接mongoose即可

mongoose.connect('mongodb://localhost:27017/example');
var db = mongoose.connection;  
db.once('open', function() {
    console.log('OPEN');
});

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谢谢sheplu，我已经更新了您的代码，而不是它所说的：