1、引入模塊

注：我這個是用了express框架來寫的一個demo

var express = require('express');
var router = express.Router();
var http = require('http');
var ejs = require('ejs');
const MongoClient = require('mongodb').MongoClient;
var url = require('url');

2、創(chuàng)建數(shù)據(jù)庫

  注解：如果沒有加上這句話 { useNewUrlParser: true, useUnifiedTopology: true }苦锨，就會報下面警告

圖一

const dbUrl = 'mongodb://127.0.0.1:7000';
MongoClient.connect(dbUrl, { useNewUrlParser: true, useUnifiedTopology: true }, function (err, client) {
  if (err) {
   console.log('數(shù)據(jù)庫鏈接失敗');
   return false;
  }
  client.close();
  })
})

3、創(chuàng)建集合

const dbUrl = 'mongodb://127.0.0.1:7000';
MongoClient.connect(dbUrl, { useNewUrlParser: true, useUnifiedTopology: true }, function (err, client) {
  if (err) {
   console.log('數(shù)據(jù)庫鏈接失敗');
   return false;
  }
  var db = client.db("dbdemo");
   db.createCollection('site', function (err, res) {
    if (err) throw err;
    console.log("創(chuàng)建集合!");
    db.close();
  });
  client.close();
  })
})

4趴泌、增刪改查等一系列數(shù)據(jù)庫操作

(1)增加數(shù)據(jù)

const dbUrl = 'mongodb://127.0.0.1:7000';

router.get('/add', function (req, res, next) {
//鏈接數(shù)據(jù)庫舟舒，mgdemo:數(shù)據(jù)庫名稱；student:集合名稱
MongoClient.connect(dbUrl, { useNewUrlParser: true, useUnifiedTopology: 
true }, function (err, client) {
  if (err) {
     console.log('數(shù)據(jù)庫鏈接失敗');
     return false;
   }
 var db = client.db("dbdemo");
 var mgobj = { name: "amy", age: 29 };
  db.collection("site").insertOne(mgobj, function (err, result) {
  if (err) {throw err;}
  res.send("增加數(shù)據(jù)成功");
  client.close();
  })
 })
});

(2).修改數(shù)據(jù)

router.get('/edit', function (req, res) {
MongoClient.connect(dbUrl, { useNewUrlParser: true, useUnifiedTopology: true }, function (err, client) {
if (err) {
  console.log("數(shù)據(jù)庫鏈接失敗");
  return false;
}
var db = client.db("mgdemo");
db.collection("student").updateOne({ name: "zhangsan" }, { $set: { age: 90 } }, function (err, result) {
  if (err) throw err;
  res.send("數(shù)據(jù)庫修改成功");
  client.close();
  })
  })
})

(3).查詢數(shù)據(jù)

注：查詢數(shù)據(jù)渲染ejs模版有兩種方式
    1嗜憔、 res.render('index', { 'list': list, title: '這是一個ejs的后臺模板引擎' })
    2秃励、 ejs.renderFile('views/index.ejs', { 'list': list, title: '這是一個ejs的后臺模板引擎' }, (err, result) => res.send(result);})

圖二

router.get('/', function (req, res) {
MongoClient.connect(dbUrl, { useNewUrlParser: true, useUnifiedTopology: true }, (err, client) => {
if (err) throw err;
let db = client.db("dbdemo");
let userRel = db.collection("site").find();
let list = [];
userRel.each((error, col) => {
  if (error) throw error;
  if (col != null) {
    list.push(col);
  } else {
    // ejs渲染模版
    // res.render('index', { 'list': list, title: '這是一個ejs的后臺模板引擎' })
    ejs.renderFile('views/index.ejs', { 'list': list, title: '這是一個ejs的后臺模板引擎' }, (err, result) => {
      res.send(result);
    })
  }
  client.close();
  })
 })
})

(4)、刪除數(shù)據(jù)

router.get('/delete', function (req, res, next) {
MongoClient.connect(dbUrl, { useNewUrlParser: true, useUnifiedTopology: true }, (err, client) => {
if (err) throw err;
var db = client.db("dbdemo");
let query = url.parse(req.url, true).query;

db.collection('site').deleteOne(query, (error, result) => {
  if (error) throw error;
  res.send('刪除成功');
  client.close();
  })
  })
})