MongoDB使用mongodb driver api连接mongo并增删改查（mongodb module）

Posted 2022-11-14 _less is more

1、下载4.0的driver

npm install mongodb@4.0

2、兼容性表，来源

不完全截图

3、下载mongodb 5镜像

docker run --rm -d -p 27017:27017 mongo:5

进入容器

docker exec -it 26d83e6bb443 /bin/bash

4、如果需要用config文件

可以用config module，下载

npm install config

在js里引用，其中process.env.NODE_ENV是设置config/下配置文件的名称

process.env.NODE_ENV = 'mongo';

const config = require('config');

const port = config.get('port');
const host = config.get('host');
const db = config.get('db');
const opts = config.get('opts');

console.log(port, host, db, opts);

如果不想下载config module，也可以直接读取config

const config = require('./config/mongo.json');

const port = config.port;
const host = config.host;
const db = config.db;
const opts = config.opts;

console.log(port, host, db, opts);

最后两种方法输出效果一样

4、demo应用，参考

json file

"host":"localhost","port":"27017","db":"ee547_hw","opts":"useUnifiedTopology":true

js文件

'use strict';

const  MongoClient  = require('mongodb');

function readConfig() 
    try 
        const config = require('./config/mongo.json');
        return config;
     catch (err) 
        // console.log(err);
        process.exit(2);
    


const config = readConfig();

const port = config.port;
const host = config.host;
const url = `mongodb://$host:$port`;
const dbName = config.db;
const opts = config.opts;

// Connect using MongoClient
const mongoClient = new MongoClient(url, opts);

// CRUD
mongoClient.connect(async function(err, client) 
    if (err) process.exit(5);
	
	// client 连接数据库管理系统成功后，连接到dbName数据库
    const db = client.db(dbName);

	// 删除已存在的collection，不存在也不影响
    await db.dropCollection("xx").then(
        (value) => console.log(value);,
        (error) => console.log("collection xx may not exist.");
    );
    await db.dropCollection("player").then(
        (value) => console.log(value);,
        (error) => console.log("collection player may not exist.");
    );
    await db.dropCollection("xxx").then(
        (value) => console.log(value);,
        (error) => console.log("collection xxx may not exist.");
    );

	// 访问player collection
    const col = db.collection('player');
    
    // 插入
    await col.insertMany([name: "as", sex: "a", name: "bx", sex: "b"]).then(
        function(value) 
            console.log(value.insertedIds);
        ,
        function(error) 
            console.log(error);
        
    );

	// 输出
    col.find().toArray(function(err, items) 
        console.log(items);
    );

	// 删除
    col.deleteOne(name:'as');

    col.find().toArray(function(err, items) 
        console.log(items);
    );

	// 修改
    col.updateMany(name:'bx', $set: name: "xixixi");

    col.find().toArray(function(err, items) 
        console.log(items);
    );

	// 不存在则在插入document时自动创建该collection
    const xxx = db.collection('xxx');

    await xxx.insertMany([name: "x1", sex: "1", name: "x2", sex: "2"]).then(
        function(value) 
            console.log(value.insertedIds);
        ,
        function(error) 
            console.log(error);
        
    );
    // 查找
    xxx.find().toArray(function(err, items) 
        console.log(items);
        client.close();
    );
);

5、也可以连接后，用另外的函数进行数据操作，操作时每一步await Promise的执行，最后close client connection

'use strict';

const  MongoClient  = require('mongodb');

function readConfig() 
    try 
        const config = require('./config/mongo.json');
        return config;
     catch (err) 
        // console.log(err);
        process.exit(2);
    


const config = readConfig();

const port = config.port;
const host = config.host;
const url = `mongodb://$host:$port`;
const dbName = config.db;
const opts = config.opts;

// Connect using MongoClient
const client = new MongoClient(url, opts);

// CRUD
client.connect(async function(err, cli) 
    if (err) process.exit(5);
);

const db = client.db(dbName);

async function main() 
    const col = db.collection('player');
    
    await col.insertMany([name: "bx", sex: "b"]).then(
        function(value) 
            console.log(value.insertedIds);
        ,
        function(error) 
            console.log(error);
        
    );
    
    await col.findOne().then(
        function(value) 
            console.log(value);
        ,
        function(error) 
            console.log(error);
        
    );

    return 'done.';


main()
    .then(console.log)
    .catch(console.error)
    .finally(() => client.close());