在 Node.js 中操作 MongoDB

参考：

• 在服务端操作 MongoDB：https://docs.mongodb.com/drivers/
• 在 Node.js 中操作 MongoDB：https://docs.mongodb.com/drivers/node/

初始化示例项目

mkdir node-mongodb-demo
cd node-mongodb-demo
npm init -y
npm install mongodb

连接到 MongoDB

const { MongoClient } = require("mongodb");
// Connection URI
const uri =
  "mongo://127.0.0.1:27017";
// Create a new MongoClient
const client = new MongoClient(uri);
async function run() {
  try {
    // Connect the client to the server
    await client.connect();
    // Establish and verify connection
    await client.db("admin").command({ ping: 1 });
    console.log("Connected successfully to server");
  } catch () {
    console.log('Connect failed')
  } finally {
    // Ensures that the client will close when you finish/error
    await client.close();
  }
}
run()

CRUD 操作

CRUD（创建，读取，更新，删除）操作使您可以处理存储在 MongoDB 中的数据。

创建文档

插入一个：

const pizzaDocument = {
  name: "Neapolitan pizza",
  shape: "round",
  toppings: [ "San Marzano tomatoes", "mozzarella di bufala cheese" ],
};
const result = await pizzaCollection.insertOne(pizzaDocument);
console.dir(result.insertedCount);

插入多个：

const pizzaDocuments = [
  { name: "Sicilian pizza", shape: "square" },
  { name: "New York pizza", shape: "round" },
  { name: "Grandma pizza", shape: "square" },
];
const result = pizzaCollection.insertMany(pizzaDocuments);
console.dir(result.insertedCount);

查询文档

const findResult = await orders.find({
  name: "Lemony Snicket",
  date: {
    $gte: new Date(new Date().setHours(00, 00, 00)),
    $lt: new Date(new Date().setHours(23, 59, 59)),
  },
});

删除文档

const doc = {
  pageViews: {
    $gt: 10,
    $lt: 32768
  }
};
// 删除符合条件的单个文档
const deleteResult = await collection.deleteOne(doc);
console.dir(deleteResult.deletedCount);
// 删除符合条件的多个文档
const deleteManyResult = await collection.deleteMany(doc);
console.dir(deleteManyResult.deletedCount);

修改文档

更新1个文档：

const filter = { _id: 465 };
// update the value of the 'z' field to 42
const updateDocument = {
   $set: {
      z: 42,
   },
};
// 更新多个
const result = await collection.updateOne(filter, updateDocument);
// 更新多个
const result = await collection.updateMany(filter, updateDocument);

替换文档：

const filter = { _id: 465 };
// replace the matched document with the replacement document
const replacementDocument = {
   z: 42,
};
const result = await collection.replaceOne(filter, replacementDocument);