Mengkueri data di Azure Cosmos DB untuk MongoDB menggunakan JavaScript

BERLAKU UNTUK: MongoDB

Gunakan kueri dan alur agregasi untuk menemukan dan memanipulasi dokumen dalam koleksi.

Catatan

Contoh cuplikan kode tersedia di GitHub sebagai proyek JavaScript.

API untuk dokumentasi | referensi MongoDB Paket MongoDB (npm)

Kueri untuk dokumen

Untuk menemukan dokumen, gunakan kueri untuk menentukan bagaimana dokumen ditemukan.

// assume doc exists

const product = {
  _id: new ObjectId('62b1f43a9446918500c875c5'),
  category: 'gear-surf-surfboards',
  name: 'Yamba Surfboard 7',
  quantity: 12,
  sale: false,
};

// For unsharded database: use id
const query1 = { _id: new ObjectId(product._id) };
const foundById = await client
  .db('adventureworks')
  .collection('products')
  .findOne(query1);
console.log(
  `Read doc:\t\n${Object.keys(foundById).map(key => `\t${key}: ${foundById[key]}\n`)}`
);

// For sharded database: point read doc from collection using the id and partitionKey
const query2 = { _id: new ObjectId(product._id), category: product.category };
const foundByIdAndPartitionKey = await client
  .db('adventureworks')
  .collection('products')
  .findOne(query2);
console.log(
  `Read doc 2:\t\n${Object.keys(foundByIdAndPartitionKey).map(key => `\t${key}: ${foundByIdAndPartitionKey[key]}\n`)}`
);

// Find one by unique doc property value
const query3 = { name: product.name };
const foundByUniqueValue = await client
  .db('adventureworks')
  .collection('products')
  .findOne(query3);
console.log(
  `Read doc 3:\t\n${Object.keys(foundByUniqueValue).map(key => `\t${key}: ${foundByUniqueValue[key]}\n`)}`
);

// Find one (with many that match query) still returns one doc
const query4 = { category: product.category };
const foundByNonUniqueValue = await client
  .db('adventureworks')
  .collection('products')
  .findOne(query4);
console.log(
  `Read doc 4:\t\n${Object.keys(foundByNonUniqueValue).map(key => `\t${key}: ${foundByNonUniqueValue[key]}\n`)}`
);

// Find all that match query
const query5 = { category: product.category };
const foundAll = await client
  .db('adventureworks')
  .collection('products')
  .find(query5)
  .sort({ _id: 1 })
  .toArray();
console.log(
  `Matching all in product category:\n${foundAll.map(doc => `\t${doc._id}: ${doc.name}\n`)}`
);

// Find all in collection with empty query {}
const foundAll2 = await client
  .db('adventureworks')
  .collection('products')
  .find({})
  .toArray();
console.log(
  `All docs:\n${foundAll2.map(doc => `\t${doc._id}: ${doc.name}\n`)}`
);

// Pagination - next 5 docs
// sort by name require an index on name
const nextFiveDocs = await client
  .db('adventureworks')
  .collection('products')
  .find({})
  .sort({ name: 1 })
  .skip(5)
  .limit(5)
  .toArray();
console.log(
  `Next 5 docs:\n${nextFiveDocs.map(doc => `\t${doc._id}: ${doc.name}\n`)}`
);

Cuplikan kode sebelumnya menampilkan contoh output konsol berikut:

Read doc:
        _id: 62b1f43a9446918500c875c5
,       name: Yamba Surfboard-13
,       category: gear-surf-surfboards
,       quantity: 20
,       sale: false
,       discontinued: true

Read doc 2:
        _id: 62b1f43a9446918500c875c5
,       name: Yamba Surfboard-13
,       category: gear-surf-surfboards
,       quantity: 20
,       sale: false
,       discontinued: true

Read doc 3:
        _id: 62b23a371a09ed6441e5ee31
,       category: gear-surf-surfboards
,       name: Yamba Surfboard 7
,       quantity: 5
,       sale: true
,       discontinued: true

Read doc 4:
        _id: 62b1f43a9446918500c875c5
,       name: Yamba Surfboard-13
,       category: gear-surf-surfboards
,       quantity: 20
,       sale: false
,       discontinued: true

Matching all in product category:
        62b1f43a9446918500c875c5: Yamba Surfboard-13
,       62b1f4670c7af8c2942b7c10: Yamba Surfboard-3
,       62b1f46fa6546d2afb5715ac: Yamba Surfboard-90
,       62b1f474e4b43498c05d295b: Yamba Surfboard-9

All docs:
        62b1f43a9446918500c875c5: Yamba Surfboard-13
,       62b1f4670c7af8c2942b7c10: Yamba Surfboard-3
,       62b1f46fa6546d2afb5715ac: Yamba Surfboard-90
,       62b1f474e4b43498c05d295b: Yamba Surfboard-9
,       62b1f47896aa8cfa280edf2d: Yamba Surfboard-55
,       62b1f47dacbf04e86c8abf25: Yamba Surfboard-11
,       62b1f4804ee53f4c5c44778c: Yamba Surfboard-97
,       62b1f492ff69395b30a03169: Yamba Surfboard-93
,       62b23a371a09ed6441e5ee30: Yamba Surfboard 3
,       62b23a371a09ed6441e5ee31: Yamba Surfboard 7

All docs:
        62b1f43a9446918500c875c5: Yamba Surfboard-13
,       62b1f4670c7af8c2942b7c10: Yamba Surfboard-3
,       62b1f46fa6546d2afb5715ac: Yamba Surfboard-90
,       62b1f474e4b43498c05d295b: Yamba Surfboard-9
,       62b1f47896aa8cfa280edf2d: Yamba Surfboard-55
,       62b1f47dacbf04e86c8abf25: Yamba Surfboard-11
,       62b1f4804ee53f4c5c44778c: Yamba Surfboard-97
,       62b1f492ff69395b30a03169: Yamba Surfboard-93
,       62b23a371a09ed6441e5ee30: Yamba Surfboard 3
,       62b23a371a09ed6441e5ee31: Yamba Surfboard 7

done

Alur agregasi

Alur agregasi berguna untuk mengisolasi komputasi kueri yang mahal, transformasi, dan pemrosesan lainnya di server Azure Cosmos DB Anda, alih-alih melakukan operasi ini pada klien.

Untuk dukungan alur agregasi tertentu, lihat hal berikut:

Sintaks alur agregasi

Alur adalah array dengan serangkaian tahapan sebagai objek JSON.

const pipeline = [
    stage1,
    stage2
]

Sintaks tahapan alur

Tahapan menentukan operasi dan data yang diterapkannya, seperti:

$match - temukan dokumen
$addFields - tambahkan bidang ke kursor, biasanya dari tahap sebelumnya
$limit - membatasi jumlah hasil yang dikembalikan dalam kursor
$project - meneruskan bidang baru atau yang sudah ada, dapat menjadi bidang komputasi
$group - mengelompokkan hasil menurut bidang atau bidang dalam alur
$sort - mengurutkan hasil

// reduce collection to relative documents
const matchStage = {
    '$match': {
        'categoryName': { $regex: 'Bikes' },
    }
}

// sort documents on field `name`
const sortStage = { 
    '$sort': { 
        "name": 1 
    } 
},

Mengagregasi alur untuk mendapatkan kursor yang dapat diulang

Alur diagregasi untuk menghasilkan kursor yang dapat diulang.

const db = 'adventureworks';
const collection = 'products';

const aggCursor = client.db(databaseName).collection(collectionName).aggregate(pipeline);

await aggCursor.forEach(product => {
    console.log(JSON.stringify(product));
});

Menggunakan alur agregasi di JavaScript

Gunakan alur untuk menyimpan pemrosesan data di server sebelum kembali ke klien.

Contoh data produk

Agregasi di bawah ini menggunakan koleksi produk sampel dengan data dalam bentuk:

[
    {
        "_id": "08225A9E-F2B3-4FA3-AB08-8C70ADD6C3C2",
        "categoryId": "75BF1ACB-168D-469C-9AA3-1FD26BB4EA4C",
        "categoryName": "Bikes, Touring Bikes",
        "sku": "BK-T79U-50",
        "name": "Touring-1000 Blue, 50",
        "description": "The product called \"Touring-1000 Blue, 50\"",
        "price": 2384.0700000000002,
        "tags": [
        ]
    },
    {
        "_id": "0F124781-C991-48A9-ACF2-249771D44029",
        "categoryId": "56400CF3-446D-4C3F-B9B2-68286DA3BB99",
        "categoryName": "Bikes, Mountain Bikes",
        "sku": "BK-M68B-42",
        "name": "Mountain-200 Black, 42",
        "description": "The product called \"Mountain-200 Black, 42\"",
        "price": 2294.9899999999998,
        "tags": [
        ]
    },
    {
        "_id": "3FE1A99E-DE14-4D11-B635-F5D39258A0B9",
        "categoryId": "26C74104-40BC-4541-8EF5-9892F7F03D72",
        "categoryName": "Components, Saddles",
        "sku": "SE-T924",
        "name": "HL Touring Seat/Saddle",
        "description": "The product called \"HL Touring Seat/Saddle\"",
        "price": 52.640000000000001,
        "tags": [
        ]
    },
]

Contoh 1: Subkategori produk, jumlah produk, dan harga rata-rata

Gunakan kode sampel berikut untuk melaporkan harga rata-rata di setiap subkategori produk.

// Goal: Find the average price of each product subcategory with
// the number of products in that subcategory.
// Sort by average price descending.

// Read .env file and set environment variables
import 'dotenv/config';

// Use official mongodb driver to connect to the server
import { MongoClient } from 'mongodb';

// New instance of MongoClient with connection string
// for Cosmos DB
const url = process.env.COSMOS_CONNECTION_STRING;
const client = new MongoClient(url);

export async function main() {
  try {
    // Use connect method to connect to the server
    await client.connect();

    // Group all products by category
    // Find average price of each category
    // Count # of products in each category
    const groupByCategory = {
      $group: {
        _id: '$categoryName',
        averagePrice: {
          $avg: '$price',
        },
        countOfProducts: {
          $sum: 1,
        },
      },
    };

    // Round price to 2 decimal places
    // Don't return _id
    // Rename category name help in `_id` to `categoryName`
    // Round prices to 2 decimal places
    // Rename property for countOfProducts to nProducts
    const additionalTransformations = {
      $project: {
        _id: 0,
        category: '$_id',
        nProducts: '$countOfProducts',
        averagePrice: { $round: ['$averagePrice', 2] },
      },
    };

    // Sort by average price descending
    const sort = { $sort: { $averagePrice: -1 } };

    // stages execute in order from top to bottom
    const pipeline = [groupByCategory, additionalTransformations, sort];

    const db = 'adventureworks';
    const collection = 'products';

    // Get iterable cursor
    const aggCursor = client.db(db).collection(collection).aggregate(pipeline);

    // Display each item in cursor
    await aggCursor.forEach(product => {
      console.log(JSON.stringify(product));
    });

    return 'done';
  } catch (err) {
    console.log(JSON.stringify(err));
  }
}

main()
  .then(console.log)
  .catch(console.error)
  .finally(() => {
    // Close the db and its underlying connections
    client.close();
  });

// Results:
// {"averagePrice":51.99,"category":"Clothing, Jerseys","nProducts":8}
// {"averagePrice":1683.36,"category":"Bikes, Mountain Bikes","nProducts":32}
// {"averagePrice":1597.45,"category":"Bikes, Road Bikes","nProducts":43}
// {"averagePrice":20.24,"category":"Components, Chains","nProducts":1}
// {"averagePrice":25,"category":"Accessories, Locks","nProducts":1}
// {"averagePrice":631.42,"category":"Components, Touring Frames","nProducts":18}
// {"averagePrice":9.25,"category":"Clothing, Socks","nProducts":4}
// {"averagePrice":125,"category":"Accessories, Panniers","nProducts":1}
// ... remaining fields ...

Contoh 2: Jenis sepeda dengan rentang harga

Gunakan kode sampel berikut untuk melaporkan Bikes subkategori.

// Goal: Find the price range for the different bike subcategories.

import dotenv from 'dotenv';
import path from 'path';
const __dirname = path.resolve();

dotenv.config({ path: path.resolve(__dirname, '../.env') });

// Use official mongodb driver to connect to the server
import { MongoClient } from 'mongodb';

// New instance of MongoClient with connection string
// for Cosmos DB
const url = process.env.COSMOS_CONNECTION_STRING;
const client = new MongoClient(url);

export async function main() {
  try {
    // Use connect method to connect to the server
    await client.connect();

    const categoryName = 'Bikes';

    const findAllBikes = {
      $match: {
        categoryName: { $regex: categoryName },
      },
    };

    // Convert 'Bikes, Touring Bikes' to ['Bikes', 'Touring Bikes']
    const splitStringIntoCsvArray = {
      $addFields: {
        categories: { $split: ['$categoryName', ', '] },
      },
    };

    // Remove first element from array
    // Converts ['Bikes', 'Touring Bikes'] to ['Touring Bikes']
    const removeFirstElement = {
      $addFields: {
        subcategory: {
          $slice: [
            '$categories',
            1,
            { $subtract: [{ $size: '$categories' }, 1] },
          ],
        },
      },
    };

    // Group items by book subcategory, and find min, avg, and max price
    const groupBySubcategory = {
      $group: {
        _id: '$subcategory',
        maxPrice: {
          $max: '$price',
        },
        averagePrice: {
          $avg: '$price',
        },
        minPrice: {
          $min: '$price',
        },
        countOfProducts: {
          $sum: 1,
        },
      },
    };

    // Miscellaneous transformations
    // Don't return _id
    // Convert subcategory from array of 1 item to string in `name`
    // Round prices to 2 decimal places
    // Rename property for countOfProducts to nProducts
    const additionalTransformations = {
      $project: {
        _id: 0,
        name: { $arrayElemAt: ['$_id', 0] },
        nProducts: '$countOfProducts',
        min: { $round: ['$minPrice', 2] },
        avg: { $round: ['$averagePrice', 2] },
        max: { $round: ['$maxPrice', 2] },
      },
    };

    // Sort by subcategory
    const sortBySubcategory = { $sort: { name: 1 } };

    // stages execute in order from top to bottom
    const pipeline = [
      findAllBikes,
      splitStringIntoCsvArray,
      removeFirstElement,
      groupBySubcategory,
      additionalTransformations,
      sortBySubcategory,
    ];

    const db = 'adventureworks';
    const collection = 'products';

    // Get iterable cursor
    const aggCursor = client.db(db).collection(collection).aggregate(pipeline);

    // Display each item in cursor
    await aggCursor.forEach(product => {
      console.log(JSON.stringify(product));
    });

    return 'done';
  } catch (err) {
    console.log(JSON.stringify(err));
  }
}

main()
  .then(console.log)
  .catch(console.error)
  .finally(() => {
    // Close the db and its underlying connections
    client.close();
  });

// Results:
// {'name':'Mountain Bikes','nProducts':32,'min':539.99,'avg':1683.37,'max':3399.99}
// {'name':'Road Bikes','nProducts':43,'min':539.99,'avg':1597.45,'max':3578.27}
// {'name':'Touring Bikes','nProducts':22,'min':742.35,'avg':1425.25,'max':2384.07}

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Last updated on 2025-06-16