Find Documents查找文档

import { MongoClient } from "mongodb";

// Replace the uri string with your MongoDB deployment's connection string.将uri字符串替换为MongoDB部署的连接字符串。
const uri = "<connection string uri>";

const client = new MongoClient(uri);

async function run() {
  try {
    
    // Get the database and collection on which to run the operation获取要在其上运行操作的数据库和集合
    const database = client.db("sample_mflix");
    const movies = database.collection("movies");

    // Query for a movie that has the title 'The Room'查询标题为“房间”的电影
    const query = { title: "The Room" };

    const options = {
      // Sort matched documents in descending order by rating按评级降序排列匹配的文档
      sort: { "imdb.rating": -1 },
      // Include only the `title` and `imdb` fields in the returned document在返回的文档中仅包含“title”和“imdb”字段
      projection: { _id: 0, title: 1, imdb: 1 },
    };

    // Execute query执行查询
    const movie = await movies.findOne(query, options);

    // Print the document returned by findOne()打印findOne()返回的文档
    console.log(movie);
  } finally {
    await client.close();
  }
}
run().catch(console.dir);

import { MongoClient } from "mongodb";

// Replace the uri string with your MongoDB deployment's connection string.将uri字符串替换为MongoDB部署的连接字符串。
const uri = "<connection string uri>";

const client = new MongoClient(uri);

interface IMDB {
  rating: number;
  votes: number;
  id: number;
}

export interface Movie {
  title: string;
  year: number;
  released: Date;
  plot: string;
  type: "movie" | "series";
  imdb: IMDB;
}

type MovieSummary = Pick<Movie, "title" | "imdb">;

async function run(): Promise<void> {
  try {
    const database = client.db("sample_mflix");
    // Specifying a Schema is always optional, but it enables type hinting on finds and inserts指定模式始终是可选的，但它允许在查找和插入时进行类型提示
    const movies = database.collection<Movie>("movies");

    const movie = await movies.findOne<MovieSummary>(
      { title: "The Room" },
      {
        sort: { rating: -1 },
        projection: { _id: 0, title: 1, imdb: 1 },
      }
    );
    console.log(movie);
  } finally {
    await client.close();
  }
}
run().catch(console.dir);

import { MongoClient } from "mongodb";

// Replace the uri string with your MongoDB deployment's connection string.将uri字符串替换为MongoDB部署的连接字符串。
const uri = "<connection string uri>";

const client = new MongoClient(uri);

async function run() {
  try {
    
    // Get the database and collection on which to run the operation获取要在其上运行操作的数据库和集合
    const database = client.db("sample_mflix");
    const movies = database.collection("movies");

    // Query for movies that have a runtime less than 15 minutes查询运行时间少于15分钟的电影
    const query = { runtime: { $lt: 15 } };
    const sortFields = { title: 1 };
    const projectFields = { _id: 0, title: 1, imdb: 1 };

    // Execute query 执行查询
    const cursor = movies.find(query).sort(sortFields).project(projectFields);

    // Print a message if no documents were found如果未找到文档，则打印消息
    if ((await movies.countDocuments(query)) === 0) {
      console.log("No documents found!");
    }

    // Print returned documents打印退回的文档
    for await (const doc of cursor) {
      console.dir(doc);
    }

  } finally {
    await client.close();
  }
}
run().catch(console.dir);

import { MongoClient } from "mongodb";

// Replace the uri string with your MongoDB deployment's connection string.
const uri = "<connection string uri>";

const client = new MongoClient(uri);

type Minutes = number;

interface IMDB {
  rating: number;
  votes: number;
  id: number;
}

interface Movie {
  title: string;
  imdb: IMDB;
  runtime: Minutes;
}

async function run() {
  try {
    const database = client.db("sample_mflix");
    const movies = database.collection<Movie>("movies");

    const query = { runtime: { $lt: 15 } };
    const sortFields = { title: 1 };
    const projectFields = { _id: 0, title: 1, imdb: 1 };

    const cursor = movies.find<Movie>(query).sort(sortFields).project(projectFields);

    if ((await movies.countDocuments(query)) === 0) {
      console.warn("No documents found!");
    }

    for await (const doc of cursor) {
      console.dir(doc);
    } 
  } finally {
    await client.close();
  }
}
run().catch(console.dir);