如何从mongodb中提取数据(查找和删除)

// 连接到 MongoDB 数据库
const MongoClient = require('mongodb').MongoClient;
const url = 'mongodb://localhost:27017';
const dbName = 'mydb';

MongoClient.connect(url, function(err, client) {
    if (err) throw err;
    const db = client.db(dbName);

    // 查找所有文档
    db.collection('mycollection').find({}).toArray(function(err, result) {
        if (err) throw err;
        console.log(result);
        client.close();
    });

    // 查找特定文档
    db.collection('mycollection').find({ name: 'John' }).toArray(function(err, result) {
        if (err) throw err;
    console.log(result);
        client.close();
    });
});

// 连接到 MongoDB 数据库
const MongoClient = require('mongodb').MongoClient;
const url = 'mongodb://localhost:27017';
const dbName = 'mydb';

MongoClient.connect(url, function(err, client) {
    if (err) throw err;
    const db = client.db(dbName);

    // 删除单个文档
    db.collection('mycollection').deleteOne({ name: 'John' }, function(err, result) {
        if (err) throw err;
        console.log(result);
        client.close();
    });

    // 删除多个文档
    db.collection('mycollection').deleteMany({ age: { $gt: 30 } }, function(err, result) {
        if (err) throw err;
        console.log(result);
        client.close();
    });
});