NodeJs/ExpressJs--Mongodbデータベースに接続する(添削・修正)

8309 ワード

インストール:
npm install mongodb--save/cnpm install mogodb--save-dev
URL:https://docs.mongodb.com/getting-started/node/introduction/https://docs.mongodb.com/getting-started/node/query/ 
Mongodbを導入
var Mongo Client=require('mongodb').Mongo Client;
データベースアドレス
let data BaseUrl='mongodb://localhost:27017/データベース名;
ケース:
app.js
let express = require('express');
//      
let MongoClient = require('mongodb').MongoClient;

let app = express();

//        ,            
let dataBaseUrl = 'mongodb://localhost:27017/person';
/*
app.get('/',(req,res) => {
    //      ,        
    MongoClient.connect(dataBaseUrl,(err,db) => {
        res.writeHead(200,{"Content-Type":"text/html;Charset=utf-8"});
        if(err) {
            res.send('       !')
        }else{
            res.write('  ,         !
'); // db.collection('student').insertOne({'name':"honghong",'age':22},(err,result) => { if(err) { res.send(' !'); return; }else{ res.write(' , !'); res.end(); // db.close(); } }) } }); }); */ /* // app.get('/',(req,res) => { // , MongoClient.connect(dataBaseUrl,(err,client) => { res.writeHead(200,{"Content-Type":"text/html;Charset=utf-8"}); if(err) { res.send(' !') }else{ res.write(' , !
'); //3.0 let db = client.db("person"); db.collection('student').insertOne({'name':"honghong1",'age':22},(err,result) => { if(err) { res.send(' !'); return; }else{ res.write(' , !'); res.end(); // client.close(); } }) } }); }); */ /* // app.get('/',(req,res) => { MongoClient.connect(dataBaseUrl,(err,client) => { res.writeHead(200,{"Content-Type":"text/html;Charset=utf-8"}); if(err) { res.send(' !') }else{ res.write(' !'); let db = client.db('person'); db.collection('student').deleteMany({'name':'honghong'},(err,result) => { if(err) { res.send(' !') return false; }else{ console.log(result) res.write(" !"); res.end(); client.close() } }) } }) }) */ /* // app.get('/',(req,res) => { res.writeHead(200,{"Content-Type":"text/html;Charset=utf-8"}); MongoClient.connect(dataBaseUrl,(err,client) => { if(err){ res.send(' !'); }else{ res.write(' !'); let db = client.db('person'); db.collection('student').updateOne({'name':'honghong1'},{$set:{'age':30}},(err,result) => { if(err){ res.send(' !'); }else{ res.write(' !'); res.end(); client.close() } }) } }) }) */ /* // app.get('/',(req,res) => { res.writeHead(200,{"Content-Type":"text/html;charset=utf-8"}); MongoClient.connect(dataBaseUrl,(err,client) => { if(err) { res.send(' !') }else{ res.write(' !'); let db = client.db('person'); db.collection('student').find().toArray((err,result) => { if(err){ res.send(' !') }else{ res.write(' !'); console.log(result); console.log(result instanceof Array);//true res.end(); client.close() } }) } }) }) */ /* // app.get('/',(req,res) => { res.writeHead(200,{"Content-Type":"text/html;charset=utf-8"}); MongoClient.connect(dataBaseUrl,(err,client) => { if(err){ res.send(' !') }else{ res.write(' !'); let db = client.db('person'); db.collection('student').find().sort({"age":1}).toArray((err,result) => { if(err) { res.send(' !') }else{ res.write(' !'); console.log(result); res.end(); client.close(); } }) } }) }) */ /* // app.get('/',(req,res) => { MongoClient.connect(dataBaseUrl,(err,client) => { res.writeHead(200,{"Content-Type":"text/html;charset=utf-8"}); if(err) { res.send(' !') }else{ res.write(' !'); let db = client.db('person'); db.collection('student').find().limit(5).toArray((err,result) => { if(err) { res.send(" !") }else{ res.write(' !'); console.log(result); res.end(); client.close() } }) } }) }) */ /* // app.get('/',(req,res) => { MongoClient.connect(dataBaseUrl,(err,client) => { res.writeHead(200,{"Content-Type":"text/html;charset=utf-8"}); if(err) { res.send(' !') }else{ res.write(' !'); let db = client.db('person'); db.collection('student').find().skip(2).toArray((err,result) => { if(err){ res.send(" !") }else{ res.write(" !"); console.log(result); res.end(); client.close() } }) } }) }) */ // $lookup app.get('/',(req,res) => { MongoClient.connect(dataBaseUrl,(err,client) => { res.writeHead(200,{"Content-Type":"text/html;charset=utf8"}); if(err) { res.send(' !'); }else{ res.write(' !'); let db = client.db('person'); db.collection('student').aggregate([ { $lookup: { from:'teacher',// ( teacher ) //localField、foreignField localField:"neme",// join ( ) foreignField:"neme",// join ( ) as:'studentTeacher'// ( array) } } ]).toArray((err,result) => { if(err) { res.send(' !') }else{ res.write(' !'); // json console.log(JSON.stringify(result)); res.end(); client.close() } }) } }) }) app.listen(8002)