使用 for (v3) 的 DynamoDB 示SDK例 JavaScript - Amazon SDK for JavaScript
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Amazon SDK for JavaScript V3 API 参考指南详细描述了 Amazon SDK for JavaScript 版本 3 (V3) 的所有API操作。

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使用 for (v3) 的 DynamoDB 示SDK例 JavaScript

以下代码示例向您展示了如何使用带有 DynamoDB 的 Amazon SDK for JavaScript (v3) 来执行操作和实现常见场景。

基础知识是向您展示如何在服务中执行基本操作的代码示例。

操作是大型程序的代码摘录,必须在上下文中运行。您可以通过操作了解如何调用单个服务函数,还可以通过函数相关场景的上下文查看操作。

场景是向您展示如何通过在一个服务中调用多个函数或与其他 Amazon Web Services 服务结合来完成特定任务的代码示例。

每个示例都包含一个指向完整源代码的链接,您可以在其中找到有关如何在上下文中设置和运行代码的说明。

开始使用

以下代码示例演示如何开始使用 DynamoDB。

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

有关在中使用 DynamoDB 的更多详细信息,请参阅使用编程 DynamoDB Amazon SDK for JavaScript。 JavaScript

import { ListTablesCommand, DynamoDBClient } from "@aws-sdk/client-dynamodb"; const client = new DynamoDBClient({}); export const main = async () => { const command = new ListTablesCommand({}); const response = await client.send(command); console.log(response.TableNames.join("\n")); return response; };
  • 有关API详细信息,请参阅 “Amazon SDK for JavaScript API参考 ListTables” 中的。

基础知识

以下代码示例展示了如何:

  • 创建可保存电影数据的表。

  • 在表中加入单一电影,获取并更新此电影。

  • 将样本JSON文件中的影片数据写入表中。

  • 查询在给定年份发行的电影。

  • 扫描在年份范围内发行的电影。

  • 删除表中的电影后再删除表。

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

import { readFileSync } from "node:fs"; import { BillingMode, CreateTableCommand, DeleteTableCommand, DynamoDBClient, waitUntilTableExists, } from "@aws-sdk/client-dynamodb"; /** * This module is a convenience library. It abstracts Amazon DynamoDB's data type * descriptors (such as S, N, B, and BOOL) by marshalling JavaScript objects into * AttributeValue shapes. */ import { BatchWriteCommand, DeleteCommand, DynamoDBDocumentClient, GetCommand, PutCommand, UpdateCommand, paginateQuery, paginateScan, } from "@aws-sdk/lib-dynamodb"; // These modules are local to our GitHub repository. We recommend cloning // the project from GitHub if you want to run this example. // For more information, see https://github.com/awsdocs/aws-doc-sdk-examples. import { getUniqueName } from "@aws-doc-sdk-examples/lib/utils/util-string.js"; import { dirnameFromMetaUrl } from "@aws-doc-sdk-examples/lib/utils/util-fs.js"; import { chunkArray } from "@aws-doc-sdk-examples/lib/utils/util-array.js"; const dirname = dirnameFromMetaUrl(import.meta.url); const tableName = getUniqueName("Movies"); const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); const log = (msg) => console.log(`[SCENARIO] ${msg}`); export const main = async () => { /** * Create a table. */ const createTableCommand = new CreateTableCommand({ TableName: tableName, // This example performs a large write to the database. // Set the billing mode to PAY_PER_REQUEST to // avoid throttling the large write. BillingMode: BillingMode.PAY_PER_REQUEST, // Define the attributes that are necessary for the key schema. AttributeDefinitions: [ { AttributeName: "year", // 'N' is a data type descriptor that represents a number type. // For a list of all data type descriptors, see the following link. // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Programming.LowLevelAPI.html#Programming.LowLevelAPI.DataTypeDescriptors AttributeType: "N", }, { AttributeName: "title", AttributeType: "S" }, ], // The KeySchema defines the primary key. The primary key can be // a partition key, or a combination of a partition key and a sort key. // Key schema design is important. For more info, see // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/best-practices.html KeySchema: [ // The way your data is accessed determines how you structure your keys. // The movies table will be queried for movies by year. It makes sense // to make year our partition (HASH) key. { AttributeName: "year", KeyType: "HASH" }, { AttributeName: "title", KeyType: "RANGE" }, ], }); log("Creating a table."); const createTableResponse = await client.send(createTableCommand); log(`Table created: ${JSON.stringify(createTableResponse.TableDescription)}`); // This polls with DescribeTableCommand until the requested table is 'ACTIVE'. // You can't write to a table before it's active. log("Waiting for the table to be active."); await waitUntilTableExists({ client }, { TableName: tableName }); log("Table active."); /** * Add a movie to the table. */ log("Adding a single movie to the table."); // PutCommand is the first example usage of 'lib-dynamodb'. const putCommand = new PutCommand({ TableName: tableName, Item: { // In 'client-dynamodb', the AttributeValue would be required (`year: { N: 1981 }`) // 'lib-dynamodb' simplifies the usage ( `year: 1981` ) year: 1981, // The preceding KeySchema defines 'title' as our sort (RANGE) key, so 'title' // is required. title: "The Evil Dead", // Every other attribute is optional. info: { genres: ["Horror"], }, }, }); await docClient.send(putCommand); log("The movie was added."); /** * Get a movie from the table. */ log("Getting a single movie from the table."); const getCommand = new GetCommand({ TableName: tableName, // Requires the complete primary key. For the movies table, the primary key // is only the id (partition key). Key: { year: 1981, title: "The Evil Dead", }, // Set this to make sure that recent writes are reflected. // For more information, see https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/HowItWorks.ReadConsistency.html. ConsistentRead: true, }); const getResponse = await docClient.send(getCommand); log(`Got the movie: ${JSON.stringify(getResponse.Item)}`); /** * Update a movie in the table. */ log("Updating a single movie in the table."); const updateCommand = new UpdateCommand({ TableName: tableName, Key: { year: 1981, title: "The Evil Dead" }, // This update expression appends "Comedy" to the list of genres. // For more information on update expressions, see // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.UpdateExpressions.html UpdateExpression: "set #i.#g = list_append(#i.#g, :vals)", ExpressionAttributeNames: { "#i": "info", "#g": "genres" }, ExpressionAttributeValues: { ":vals": ["Comedy"], }, ReturnValues: "ALL_NEW", }); const updateResponse = await docClient.send(updateCommand); log(`Movie updated: ${JSON.stringify(updateResponse.Attributes)}`); /** * Delete a movie from the table. */ log("Deleting a single movie from the table."); const deleteCommand = new DeleteCommand({ TableName: tableName, Key: { year: 1981, title: "The Evil Dead" }, }); await client.send(deleteCommand); log("Movie deleted."); /** * Upload a batch of movies. */ log("Adding movies from local JSON file."); const file = readFileSync( `${dirname}../../../../resources/sample_files/movies.json`, ); const movies = JSON.parse(file.toString()); // chunkArray is a local convenience function. It takes an array and returns // a generator function. The generator function yields every N items. const movieChunks = chunkArray(movies, 25); // For every chunk of 25 movies, make one BatchWrite request. for (const chunk of movieChunks) { const putRequests = chunk.map((movie) => ({ PutRequest: { Item: movie, }, })); const command = new BatchWriteCommand({ RequestItems: { [tableName]: putRequests, }, }); await docClient.send(command); } log("Movies added."); /** * Query for movies by year. */ log("Querying for all movies from 1981."); const paginatedQuery = paginateQuery( { client: docClient }, { TableName: tableName, //For more information about query expressions, see // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Query.html#Query.KeyConditionExpressions KeyConditionExpression: "#y = :y", // 'year' is a reserved word in DynamoDB. Indicate that it's an attribute // name by using an expression attribute name. ExpressionAttributeNames: { "#y": "year" }, ExpressionAttributeValues: { ":y": 1981 }, ConsistentRead: true, }, ); /** * @type { Record<string, any>[] }; */ const movies1981 = []; for await (const page of paginatedQuery) { movies1981.push(...page.Items); } log(`Movies: ${movies1981.map((m) => m.title).join(", ")}`); /** * Scan the table for movies between 1980 and 1990. */ log("Scan for movies released between 1980 and 1990"); // A 'Scan' operation always reads every item in the table. If your design requires // the use of 'Scan', consider indexing your table or changing your design. // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/bp-query-scan.html const paginatedScan = paginateScan( { client: docClient }, { TableName: tableName, // Scan uses a filter expression instead of a key condition expression. Scan will // read the entire table and then apply the filter. FilterExpression: "#y between :y1 and :y2", ExpressionAttributeNames: { "#y": "year" }, ExpressionAttributeValues: { ":y1": 1980, ":y2": 1990 }, ConsistentRead: true, }, ); /** * @type { Record<string, any>[] }; */ const movies1980to1990 = []; for await (const page of paginatedScan) { movies1980to1990.push(...page.Items); } log( `Movies: ${movies1980to1990 .map((m) => `${m.title} (${m.year})`) .join(", ")}`, ); /** * Delete the table. */ const deleteTableCommand = new DeleteTableCommand({ TableName: tableName }); log(`Deleting table ${tableName}.`); await client.send(deleteTableCommand); log("Table deleted."); };

操作

以下代码示例显示了如何使用BatchExecuteStatement

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

使用 PartiQL 创建一批项目。

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { DynamoDBDocumentClient, BatchExecuteStatementCommand, } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const breakfastFoods = ["Eggs", "Bacon", "Sausage"]; const command = new BatchExecuteStatementCommand({ Statements: breakfastFoods.map((food) => ({ Statement: `INSERT INTO BreakfastFoods value {'Name':?}`, Parameters: [food], })), }); const response = await docClient.send(command); console.log(response); return response; };

使用 PartiQL 获取一批项目。

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { DynamoDBDocumentClient, BatchExecuteStatementCommand, } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const command = new BatchExecuteStatementCommand({ Statements: [ { Statement: "SELECT * FROM PepperMeasurements WHERE Unit=?", Parameters: ["Teaspoons"], ConsistentRead: true, }, { Statement: "SELECT * FROM PepperMeasurements WHERE Unit=?", Parameters: ["Grams"], ConsistentRead: true, }, ], }); const response = await docClient.send(command); console.log(response); return response; };

使用 PartiQL 更新一批项目。

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { DynamoDBDocumentClient, BatchExecuteStatementCommand, } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const eggUpdates = [ ["duck", "fried"], ["chicken", "omelette"], ]; const command = new BatchExecuteStatementCommand({ Statements: eggUpdates.map((change) => ({ Statement: "UPDATE Eggs SET Style=? where Variety=?", Parameters: [change[1], change[0]], })), }); const response = await docClient.send(command); console.log(response); return response; };

使用 PartiQL 删除一批项目。

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { DynamoDBDocumentClient, BatchExecuteStatementCommand, } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const command = new BatchExecuteStatementCommand({ Statements: [ { Statement: "DELETE FROM Flavors where Name=?", Parameters: ["Grape"], }, { Statement: "DELETE FROM Flavors where Name=?", Parameters: ["Strawberry"], }, ], }); const response = await docClient.send(command); console.log(response); return response; };
  • 有关API详细信息,请参阅 “Amazon SDK for JavaScript API参考 BatchExecuteStatement” 中的。

以下代码示例显示了如何使用BatchGetItem

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

此示例使用文档客户端来简化在 DynamoDB 中处理项目的过程。有关API详细信息,请参阅BatchGet

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { BatchGetCommand, DynamoDBDocumentClient } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const command = new BatchGetCommand({ // Each key in this object is the name of a table. This example refers // to a Books table. RequestItems: { Books: { // Each entry in Keys is an object that specifies a primary key. Keys: [ { Title: "How to AWS", }, { Title: "DynamoDB for DBAs", }, ], // Only return the "Title" and "PageCount" attributes. ProjectionExpression: "Title, PageCount", }, }, }); const response = await docClient.send(command); console.log(response.Responses.Books); return response; };
SDK对于 JavaScript (v2)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

// Load the AWS SDK for Node.js var AWS = require("aws-sdk"); // Set the region AWS.config.update({ region: "REGION" }); // Create DynamoDB service object var ddb = new AWS.DynamoDB({ apiVersion: "2012-08-10" }); var params = { RequestItems: { TABLE_NAME: { Keys: [ { KEY_NAME: { N: "KEY_VALUE_1" } }, { KEY_NAME: { N: "KEY_VALUE_2" } }, { KEY_NAME: { N: "KEY_VALUE_3" } }, ], ProjectionExpression: "KEY_NAME, ATTRIBUTE", }, }, }; ddb.batchGetItem(params, function (err, data) { if (err) { console.log("Error", err); } else { data.Responses.TABLE_NAME.forEach(function (element, index, array) { console.log(element); }); } });

以下代码示例显示了如何使用BatchWriteItem

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

此示例使用文档客户端来简化在 DynamoDB 中处理项目的过程。有关API详细信息,请参阅BatchWrite

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { BatchWriteCommand, DynamoDBDocumentClient, } from "@aws-sdk/lib-dynamodb"; import { readFileSync } from "node:fs"; // These modules are local to our GitHub repository. We recommend cloning // the project from GitHub if you want to run this example. // For more information, see https://github.com/awsdocs/aws-doc-sdk-examples. import { dirnameFromMetaUrl } from "@aws-doc-sdk-examples/lib/utils/util-fs.js"; import { chunkArray } from "@aws-doc-sdk-examples/lib/utils/util-array.js"; const dirname = dirnameFromMetaUrl(import.meta.url); const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const file = readFileSync( `${dirname}../../../../../resources/sample_files/movies.json`, ); const movies = JSON.parse(file.toString()); // chunkArray is a local convenience function. It takes an array and returns // a generator function. The generator function yields every N items. const movieChunks = chunkArray(movies, 25); // For every chunk of 25 movies, make one BatchWrite request. for (const chunk of movieChunks) { const putRequests = chunk.map((movie) => ({ PutRequest: { Item: movie, }, })); const command = new BatchWriteCommand({ RequestItems: { // An existing table is required. A composite key of 'title' and 'year' is recommended // to account for duplicate titles. BatchWriteMoviesTable: putRequests, }, }); await docClient.send(command); } };
  • 有关API详细信息,请参阅 “Amazon SDK for JavaScript API参考 BatchWriteItem” 中的。

SDK对于 JavaScript (v2)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

// Load the AWS SDK for Node.js var AWS = require("aws-sdk"); // Set the region AWS.config.update({ region: "REGION" }); // Create DynamoDB service object var ddb = new AWS.DynamoDB({ apiVersion: "2012-08-10" }); var params = { RequestItems: { TABLE_NAME: [ { PutRequest: { Item: { KEY: { N: "KEY_VALUE" }, ATTRIBUTE_1: { S: "ATTRIBUTE_1_VALUE" }, ATTRIBUTE_2: { N: "ATTRIBUTE_2_VALUE" }, }, }, }, { PutRequest: { Item: { KEY: { N: "KEY_VALUE" }, ATTRIBUTE_1: { S: "ATTRIBUTE_1_VALUE" }, ATTRIBUTE_2: { N: "ATTRIBUTE_2_VALUE" }, }, }, }, ], }, }; ddb.batchWriteItem(params, function (err, data) { if (err) { console.log("Error", err); } else { console.log("Success", data); } });

以下代码示例显示了如何使用CreateTable

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

import { CreateTableCommand, DynamoDBClient } from "@aws-sdk/client-dynamodb"; const client = new DynamoDBClient({}); export const main = async () => { const command = new CreateTableCommand({ TableName: "EspressoDrinks", // For more information about data types, // see https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/HowItWorks.NamingRulesDataTypes.html#HowItWorks.DataTypes and // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Programming.LowLevelAPI.html#Programming.LowLevelAPI.DataTypeDescriptors AttributeDefinitions: [ { AttributeName: "DrinkName", AttributeType: "S", }, ], KeySchema: [ { AttributeName: "DrinkName", KeyType: "HASH", }, ], ProvisionedThroughput: { ReadCapacityUnits: 1, WriteCapacityUnits: 1, }, }); const response = await client.send(command); console.log(response); return response; };
SDK对于 JavaScript (v2)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

// Load the AWS SDK for Node.js var AWS = require("aws-sdk"); // Set the region AWS.config.update({ region: "REGION" }); // Create the DynamoDB service object var ddb = new AWS.DynamoDB({ apiVersion: "2012-08-10" }); var params = { AttributeDefinitions: [ { AttributeName: "CUSTOMER_ID", AttributeType: "N", }, { AttributeName: "CUSTOMER_NAME", AttributeType: "S", }, ], KeySchema: [ { AttributeName: "CUSTOMER_ID", KeyType: "HASH", }, { AttributeName: "CUSTOMER_NAME", KeyType: "RANGE", }, ], ProvisionedThroughput: { ReadCapacityUnits: 1, WriteCapacityUnits: 1, }, TableName: "CUSTOMER_LIST", StreamSpecification: { StreamEnabled: false, }, }; // Call DynamoDB to create the table ddb.createTable(params, function (err, data) { if (err) { console.log("Error", err); } else { console.log("Table Created", data); } });

以下代码示例显示了如何使用DeleteItem

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

此示例使用文档客户端来简化在 DynamoDB 中处理项目的过程。有关API详细信息,请参阅DeleteCommand

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { DynamoDBDocumentClient, DeleteCommand } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const command = new DeleteCommand({ TableName: "Sodas", Key: { Flavor: "Cola", }, }); const response = await docClient.send(command); console.log(response); return response; };
SDK对于 JavaScript (v2)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

从表中删除项目。

// Load the AWS SDK for Node.js var AWS = require("aws-sdk"); // Set the region AWS.config.update({ region: "REGION" }); // Create the DynamoDB service object var ddb = new AWS.DynamoDB({ apiVersion: "2012-08-10" }); var params = { TableName: "TABLE", Key: { KEY_NAME: { N: "VALUE" }, }, }; // Call DynamoDB to delete the item from the table ddb.deleteItem(params, function (err, data) { if (err) { console.log("Error", err); } else { console.log("Success", data); } });

使用 DynamoDB 文档客户端从表中删除项目。

// Load the AWS SDK for Node.js var AWS = require("aws-sdk"); // Set the region AWS.config.update({ region: "REGION" }); // Create DynamoDB document client var docClient = new AWS.DynamoDB.DocumentClient({ apiVersion: "2012-08-10" }); var params = { Key: { HASH_KEY: VALUE, }, TableName: "TABLE", }; docClient.delete(params, function (err, data) { if (err) { console.log("Error", err); } else { console.log("Success", data); } });

以下代码示例显示了如何使用DeleteTable

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

import { DeleteTableCommand, DynamoDBClient } from "@aws-sdk/client-dynamodb"; const client = new DynamoDBClient({}); export const main = async () => { const command = new DeleteTableCommand({ TableName: "DecafCoffees", }); const response = await client.send(command); console.log(response); return response; };
  • 有关API详细信息,请参阅 “Amazon SDK for JavaScript API参考 DeleteTable” 中的。

SDK对于 JavaScript (v2)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

// Load the AWS SDK for Node.js var AWS = require("aws-sdk"); // Set the region AWS.config.update({ region: "REGION" }); // Create the DynamoDB service object var ddb = new AWS.DynamoDB({ apiVersion: "2012-08-10" }); var params = { TableName: process.argv[2], }; // Call DynamoDB to delete the specified table ddb.deleteTable(params, function (err, data) { if (err && err.code === "ResourceNotFoundException") { console.log("Error: Table not found"); } else if (err && err.code === "ResourceInUseException") { console.log("Error: Table in use"); } else { console.log("Success", data); } });

以下代码示例显示了如何使用DescribeTable

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

import { DescribeTableCommand, DynamoDBClient } from "@aws-sdk/client-dynamodb"; const client = new DynamoDBClient({}); export const main = async () => { const command = new DescribeTableCommand({ TableName: "Pastries", }); const response = await client.send(command); console.log(`TABLE NAME: ${response.Table.TableName}`); console.log(`TABLE ITEM COUNT: ${response.Table.ItemCount}`); return response; };
SDK对于 JavaScript (v2)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

// Load the AWS SDK for Node.js var AWS = require("aws-sdk"); // Set the region AWS.config.update({ region: "REGION" }); // Create the DynamoDB service object var ddb = new AWS.DynamoDB({ apiVersion: "2012-08-10" }); var params = { TableName: process.argv[2], }; // Call DynamoDB to retrieve the selected table descriptions ddb.describeTable(params, function (err, data) { if (err) { console.log("Error", err); } else { console.log("Success", data.Table.KeySchema); } });

以下代码示例显示了如何使用DescribeTimeToLive

SDK对于 JavaScript (v3)
import { DynamoDBClient, DescribeTimeToLiveCommand } from "@aws-sdk/client-dynamodb"; const describeTableTTL = async (tableName, region) => { const client = new DynamoDBClient({ region: region, endpoint: `https://dynamodb.${region}.amazonaws.com` }); try { const ttlDescription = await client.send(new DescribeTimeToLiveCommand({ TableName: tableName })); if (ttlDescription.TimeToLiveDescription.TimeToLiveStatus === 'ENABLED') { console.log("TTL is enabled for table %s.", tableName); } else { console.log("TTL is not enabled for table %s.", tableName); } return ttlDescription; } catch (e) { console.error(`Error describing table: ${e}`); throw e; } } // enter table name and change region if desired. describeTableTTL('your-table-name', 'us-east-1');
  • 有关API详细信息,请参阅 “Amazon SDK for JavaScript API参考 DescribeTimeToLive” 中的。

以下代码示例显示了如何使用ExecuteStatement

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

使用 PartiQL 创建项目。

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { ExecuteStatementCommand, DynamoDBDocumentClient, } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const command = new ExecuteStatementCommand({ Statement: `INSERT INTO Flowers value {'Name':?}`, Parameters: ["Rose"], }); const response = await docClient.send(command); console.log(response); return response; };

使用 PartiQL 获取项目。

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { ExecuteStatementCommand, DynamoDBDocumentClient, } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const command = new ExecuteStatementCommand({ Statement: "SELECT * FROM CloudTypes WHERE IsStorm=?", Parameters: [false], ConsistentRead: true, }); const response = await docClient.send(command); console.log(response); return response; };

使用 PartiQL 更新项目。

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { ExecuteStatementCommand, DynamoDBDocumentClient, } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const command = new ExecuteStatementCommand({ Statement: "UPDATE EyeColors SET IsRecessive=? where Color=?", Parameters: [true, "blue"], }); const response = await docClient.send(command); console.log(response); return response; };

使用 PartiQL 删除项目。

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { ExecuteStatementCommand, DynamoDBDocumentClient, } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const command = new ExecuteStatementCommand({ Statement: "DELETE FROM PaintColors where Name=?", Parameters: ["Purple"], }); const response = await docClient.send(command); console.log(response); return response; };
  • 有关API详细信息,请参阅 “Amazon SDK for JavaScript API参考 ExecuteStatement” 中的。

以下代码示例显示了如何使用GetItem

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

此示例使用文档客户端来简化在 DynamoDB 中处理项目的过程。有关API详细信息,请参阅GetCommand

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { DynamoDBDocumentClient, GetCommand } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const command = new GetCommand({ TableName: "AngryAnimals", Key: { CommonName: "Shoebill", }, }); const response = await docClient.send(command); console.log(response); return response; };
  • 有关API详细信息,请参阅 “Amazon SDK for JavaScript API参考 GetItem” 中的。

SDK对于 JavaScript (v2)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

从表中获取项目。

// Load the AWS SDK for Node.js var AWS = require("aws-sdk"); // Set the region AWS.config.update({ region: "REGION" }); // Create the DynamoDB service object var ddb = new AWS.DynamoDB({ apiVersion: "2012-08-10" }); var params = { TableName: "TABLE", Key: { KEY_NAME: { N: "001" }, }, ProjectionExpression: "ATTRIBUTE_NAME", }; // Call DynamoDB to read the item from the table ddb.getItem(params, function (err, data) { if (err) { console.log("Error", err); } else { console.log("Success", data.Item); } });

使用 DynamoDB 文档客户端从表中获取项目。

// Load the AWS SDK for Node.js var AWS = require("aws-sdk"); // Set the region AWS.config.update({ region: "REGION" }); // Create DynamoDB document client var docClient = new AWS.DynamoDB.DocumentClient({ apiVersion: "2012-08-10" }); var params = { TableName: "EPISODES_TABLE", Key: { KEY_NAME: VALUE }, }; docClient.get(params, function (err, data) { if (err) { console.log("Error", err); } else { console.log("Success", data.Item); } });

以下代码示例显示了如何使用ListTables

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

import { ListTablesCommand, DynamoDBClient } from "@aws-sdk/client-dynamodb"; const client = new DynamoDBClient({}); export const main = async () => { const command = new ListTablesCommand({}); const response = await client.send(command); console.log(response); return response; };
SDK对于 JavaScript (v2)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

// Load the AWS SDK for Node.js var AWS = require("aws-sdk"); // Set the region AWS.config.update({ region: "REGION" }); // Create the DynamoDB service object var ddb = new AWS.DynamoDB({ apiVersion: "2012-08-10" }); // Call DynamoDB to retrieve the list of tables ddb.listTables({ Limit: 10 }, function (err, data) { if (err) { console.log("Error", err.code); } else { console.log("Table names are ", data.TableNames); } });

以下代码示例显示了如何使用PutItem

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

此示例使用文档客户端来简化在 DynamoDB 中处理项目的过程。有关API详细信息,请参阅PutCommand

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { PutCommand, DynamoDBDocumentClient } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const command = new PutCommand({ TableName: "HappyAnimals", Item: { CommonName: "Shiba Inu", }, }); const response = await docClient.send(command); console.log(response); return response; };
  • 有关API详细信息,请参阅 “Amazon SDK for JavaScript API参考 PutItem” 中的。

SDK对于 JavaScript (v2)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

将项目放入表中。

// Load the AWS SDK for Node.js var AWS = require("aws-sdk"); // Set the region AWS.config.update({ region: "REGION" }); // Create the DynamoDB service object var ddb = new AWS.DynamoDB({ apiVersion: "2012-08-10" }); var params = { TableName: "CUSTOMER_LIST", Item: { CUSTOMER_ID: { N: "001" }, CUSTOMER_NAME: { S: "Richard Roe" }, }, }; // Call DynamoDB to add the item to the table ddb.putItem(params, function (err, data) { if (err) { console.log("Error", err); } else { console.log("Success", data); } });

使用 DynamoDB 文档客户端将项目放入表中。

// Load the AWS SDK for Node.js var AWS = require("aws-sdk"); // Set the region AWS.config.update({ region: "REGION" }); // Create DynamoDB document client var docClient = new AWS.DynamoDB.DocumentClient({ apiVersion: "2012-08-10" }); var params = { TableName: "TABLE", Item: { HASHKEY: VALUE, ATTRIBUTE_1: "STRING_VALUE", ATTRIBUTE_2: VALUE_2, }, }; docClient.put(params, function (err, data) { if (err) { console.log("Error", err); } else { console.log("Success", data); } });

以下代码示例显示了如何使用Query

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

此示例使用文档客户端来简化在 DynamoDB 中处理项目的过程。有关API详细信息,请参阅QueryCommand

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { QueryCommand, DynamoDBDocumentClient } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const command = new QueryCommand({ TableName: "CoffeeCrop", KeyConditionExpression: "OriginCountry = :originCountry AND RoastDate > :roastDate", ExpressionAttributeValues: { ":originCountry": "Ethiopia", ":roastDate": "2023-05-01", }, ConsistentRead: true, }); const response = await docClient.send(command); console.log(response); return response; };
SDK对于 JavaScript (v2)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

// Load the AWS SDK for Node.js var AWS = require("aws-sdk"); // Set the region AWS.config.update({ region: "REGION" }); // Create DynamoDB document client var docClient = new AWS.DynamoDB.DocumentClient({ apiVersion: "2012-08-10" }); var params = { ExpressionAttributeValues: { ":s": 2, ":e": 9, ":topic": "PHRASE", }, KeyConditionExpression: "Season = :s and Episode > :e", FilterExpression: "contains (Subtitle, :topic)", TableName: "EPISODES_TABLE", }; docClient.query(params, function (err, data) { if (err) { console.log("Error", err); } else { console.log("Success", data.Items); } });

以下代码示例显示了如何使用Scan

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

此示例使用文档客户端来简化在 DynamoDB 中处理项目的过程。有关API详细信息,请参阅ScanCommand

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { DynamoDBDocumentClient, ScanCommand } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const command = new ScanCommand({ ProjectionExpression: "#Name, Color, AvgLifeSpan", ExpressionAttributeNames: { "#Name": "Name" }, TableName: "Birds", }); const response = await docClient.send(command); for (const bird of response.Items) { console.log(`${bird.Name} - (${bird.Color}, ${bird.AvgLifeSpan})`); } return response; };
SDK对于 JavaScript (v2)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

// Load the AWS SDK for Node.js. var AWS = require("aws-sdk"); // Set the AWS Region. AWS.config.update({ region: "REGION" }); // Create DynamoDB service object. var ddb = new AWS.DynamoDB({ apiVersion: "2012-08-10" }); const params = { // Specify which items in the results are returned. FilterExpression: "Subtitle = :topic AND Season = :s AND Episode = :e", // Define the expression attribute value, which are substitutes for the values you want to compare. ExpressionAttributeValues: { ":topic": { S: "SubTitle2" }, ":s": { N: 1 }, ":e": { N: 2 }, }, // Set the projection expression, which are the attributes that you want. ProjectionExpression: "Season, Episode, Title, Subtitle", TableName: "EPISODES_TABLE", }; ddb.scan(params, function (err, data) { if (err) { console.log("Error", err); } else { console.log("Success", data); data.Items.forEach(function (element, index, array) { console.log( "printing", element.Title.S + " (" + element.Subtitle.S + ")" ); }); } });

以下代码示例显示了如何使用UpdateItem

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

此示例使用文档客户端来简化在 DynamoDB 中处理项目的过程。有关API详细信息,请参阅UpdateCommand

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { DynamoDBDocumentClient, UpdateCommand } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const command = new UpdateCommand({ TableName: "Dogs", Key: { Breed: "Labrador", }, UpdateExpression: "set Color = :color", ExpressionAttributeValues: { ":color": "black", }, ReturnValues: "ALL_NEW", }); const response = await docClient.send(command); console.log(response); return response; };
  • 有关API详细信息,请参阅 “Amazon SDK for JavaScript API参考 UpdateItem” 中的。

以下代码示例显示了如何使用UpdateTimeToLive

SDK对于 JavaScript (v3)

在现有 DynamoDB 表TTL上启用。

import { DynamoDBClient, UpdateTimeToLiveCommand } from "@aws-sdk/client-dynamodb"; const enableTTL = async (tableName, ttlAttribute) => { const client = new DynamoDBClient({}); const params = { TableName: tableName, TimeToLiveSpecification: { Enabled: true, AttributeName: ttlAttribute } }; try { const response = await client.send(new UpdateTimeToLiveCommand(params)); if (response.$metadata.httpStatusCode === 200) { console.log(`TTL enabled successfully for table ${tableName}, using attribute name ${ttlAttribute}.`); } else { console.log(`Failed to enable TTL for table ${tableName}, response object: ${response}`); } return response; } catch (e) { console.error(`Error enabling TTL: ${e}`); throw e; } }; // call with your own values enableTTL('ExampleTable', 'exampleTtlAttribute');

在现有 DynamoDB 表TTL上禁用。

import { DynamoDBClient, UpdateTimeToLiveCommand } from "@aws-sdk/client-dynamodb"; const disableTTL = async (tableName, ttlAttribute) => { const client = new DynamoDBClient({}); const params = { TableName: tableName, TimeToLiveSpecification: { Enabled: false, AttributeName: ttlAttribute } }; try { const response = await client.send(new UpdateTimeToLiveCommand(params)); if (response.$metadata.httpStatusCode === 200) { console.log(`TTL disabled successfully for table ${tableName}, using attribute name ${ttlAttribute}.`); } else { console.log(`Failed to disable TTL for table ${tableName}, response object: ${response}`); } return response; } catch (e) { console.error(`Error disabling TTL: ${e}`); throw e; } }; // call with your own values disableTTL('ExampleTable', 'exampleTtlAttribute');
  • 有关API详细信息,请参阅 “Amazon SDK for JavaScript API参考 UpdateTimeToLive” 中的。

场景

以下代码示例演示如何构建一个应用程序,该应用程序可将数据提交到 Amazon DynamoDB 表,并在用户更新表时通知您。

SDK对于 JavaScript (v3)

此示例说明如何构建一个应用程序,让用户能够使用亚马逊简单通知服务 (Amazon) 向 Amazon DynamoDB 表提交数据,以及如何使用亚马逊简单通知服务 (Amazon) 向管理员发送短信。SNS

有关如何设置和运行的完整源代码和说明,请参阅上的完整示例GitHub

该示例也可在 Amazon SDK for JavaScript v3 开发人员指南中找到。

本示例中使用的服务
  • DynamoDB

  • Amazon SNS

以下代码示例显示了如何有条件地更新项目。TTL

SDK对于 JavaScript (v3)

使用TTL条件更新表中现有 DynamoDB 项目。

import { DynamoDBClient, UpdateItemCommand } from "@aws-sdk/client-dynamodb"; import { marshall, unmarshall } from "@aws-sdk/util-dynamodb"; const updateDynamoDBItem = async (tableName, region, partitionKey, sortKey, newAttribute) => { const client = new DynamoDBClient({ region: region, endpoint: `https://dynamodb.${region}.amazonaws.com` }); const currentTime = Math.floor(Date.now() / 1000); const params = { TableName: tableName, Key: marshall({ artist: partitionKey, album: sortKey }), UpdateExpression: "SET newAttribute = :newAttribute", ConditionExpression: "expireAt > :expiration", ExpressionAttributeValues: marshall({ ':newAttribute': newAttribute, ':expiration': currentTime }), ReturnValues: "ALL_NEW" }; try { const response = await client.send(new UpdateItemCommand(params)); const responseData = unmarshall(response.Attributes); console.log("Item updated successfully: ", responseData); return responseData; } catch (error) { if (error.name === "ConditionalCheckFailedException") { console.log("Condition check failed: Item's 'expireAt' is expired."); } else { console.error("Error updating item: ", error); } throw error; } }; // Enter your values here updateDynamoDBItem('your-table-name', "us-east-1",'your-partition-key-value', 'your-sort-key-value', 'your-new-attribute-value');
  • 有关API详细信息,请参阅 “Amazon SDK for JavaScript API参考 UpdateItem” 中的。

以下代码示例演示如何创建无服务器应用程序,让用户能够使用标签管理照片。

SDK对于 JavaScript (v3)

演示如何开发照片资产管理应用程序,该应用程序使用 Amazon Rekognition 检测图像中的标签并将其存储以供日后检索。

有关如何设置和运行的完整源代码和说明,请参阅上的完整示例 GitHub

要深入了解这个例子的起源,请参阅 Amazon 社区上的博文。

本示例中使用的服务
  • API网关

  • DynamoDB

  • Lambda

  • Amazon Rekognition

  • Amazon S3

  • Amazon SNS

以下代码示例显示了如何使用创建项目TTL。

SDK对于 JavaScript (v3)
import { DynamoDBClient, PutItemCommand } from "@aws-sdk/client-dynamodb"; function createDynamoDBItem(table_name, region, partition_key, sort_key) { const client = new DynamoDBClient({ region: region, endpoint: `https://dynamodb.${region}.amazonaws.com` }); // Get the current time in epoch second format const current_time = Math.floor(new Date().getTime() / 1000); // Calculate the expireAt time (90 days from now) in epoch second format const expire_at = Math.floor((new Date().getTime() + 90 * 24 * 60 * 60 * 1000) / 1000); // Create DynamoDB item const item = { 'partitionKey': {'S': partition_key}, 'sortKey': {'S': sort_key}, 'createdAt': {'N': current_time.toString()}, 'expireAt': {'N': expire_at.toString()} }; const putItemCommand = new PutItemCommand({ TableName: table_name, Item: item, ProvisionedThroughput: { ReadCapacityUnits: 1, WriteCapacityUnits: 1, }, }); client.send(putItemCommand, function(err, data) { if (err) { console.log("Exception encountered when creating item %s, here's what happened: ", data, ex); throw err; } else { console.log("Item created successfully: %s.", data); return data; } }); } // use your own values createDynamoDBItem('your-table-name', 'us-east-1', 'your-partition-key-value', 'your-sort-key-value');
  • 有关API详细信息,请参阅 “Amazon SDK for JavaScript API参考 PutItem” 中的。

以下代码示例显示了如何从浏览器调用 Amazon Lambda 函数。

SDK对于 JavaScript (v2)

您可以创建一个基于浏览器的应用程序,该应用程序使用 Amazon Lambda 函数更新包含用户选择的 Amazon DynamoDB 表。

有关如何设置和运行的完整源代码和说明,请参阅上的完整示例GitHub

本示例中使用的服务
  • DynamoDB

  • Lambda

SDK对于 JavaScript (v3)

您可以创建一个基于浏览器的应用程序,该应用程序使用 Amazon Lambda 函数更新包含用户选择的 Amazon DynamoDB 表。此应用程序使用 Amazon SDK for JavaScript v3。

有关如何设置和运行的完整源代码和说明,请参阅上的完整示例GitHub

本示例中使用的服务
  • DynamoDB

  • Lambda

以下代码示例展示了如何:

  • 通过运行多个SELECT语句获取一批项目。

  • 通过运行多个INSERT语句来添加一批项目。

  • 通过运行多个UPDATE语句来更新一批项目。

  • 通过运行多个DELETE语句来删除一批项目。

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

执行批处理 PartiQL 语句。

import { BillingMode, CreateTableCommand, DeleteTableCommand, DescribeTableCommand, DynamoDBClient, waitUntilTableExists, } from "@aws-sdk/client-dynamodb"; import { DynamoDBDocumentClient, BatchExecuteStatementCommand, } from "@aws-sdk/lib-dynamodb"; import { ScenarioInput } from "@aws-doc-sdk-examples/lib/scenario"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); const log = (msg) => console.log(`[SCENARIO] ${msg}`); const tableName = "Cities"; export const main = async (confirmAll = false) => { /** * Delete table if it exists. */ try { await client.send(new DescribeTableCommand({ TableName: tableName })); // If no error was thrown, the table exists. const input = new ScenarioInput( "deleteTable", `A table named ${tableName} already exists. If you choose not to delete this table, the scenario cannot continue. Delete it?`, { type: "confirm", confirmAll }, ); const deleteTable = await input.handle({}, { confirmAll }); if (deleteTable) { await client.send(new DeleteTableCommand({ tableName })); } else { console.warn( "Scenario could not run. Either delete ${tableName} or provide a unique table name.", ); return; } } catch (caught) { if ( caught instanceof Error && caught.name === "ResourceNotFoundException" ) { // Do nothing. This means the table is not there. } else { throw caught; } } /** * Create a table. */ log("Creating a table."); const createTableCommand = new CreateTableCommand({ TableName: tableName, // This example performs a large write to the database. // Set the billing mode to PAY_PER_REQUEST to // avoid throttling the large write. BillingMode: BillingMode.PAY_PER_REQUEST, // Define the attributes that are necessary for the key schema. AttributeDefinitions: [ { AttributeName: "name", // 'S' is a data type descriptor that represents a number type. // For a list of all data type descriptors, see the following link. // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Programming.LowLevelAPI.html#Programming.LowLevelAPI.DataTypeDescriptors AttributeType: "S", }, ], // The KeySchema defines the primary key. The primary key can be // a partition key, or a combination of a partition key and a sort key. // Key schema design is important. For more info, see // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/best-practices.html KeySchema: [{ AttributeName: "name", KeyType: "HASH" }], }); await client.send(createTableCommand); log(`Table created: ${tableName}.`); /** * Wait until the table is active. */ // This polls with DescribeTableCommand until the requested table is 'ACTIVE'. // You can't write to a table before it's active. log("Waiting for the table to be active."); await waitUntilTableExists({ client }, { TableName: tableName }); log("Table active."); /** * Insert items. */ log("Inserting cities into the table."); const addItemsStatementCommand = new BatchExecuteStatementCommand({ // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ql-reference.insert.html Statements: [ { Statement: `INSERT INTO ${tableName} value {'name':?, 'population':?}`, Parameters: ["Alachua", 10712], }, { Statement: `INSERT INTO ${tableName} value {'name':?, 'population':?}`, Parameters: ["High Springs", 6415], }, ], }); await docClient.send(addItemsStatementCommand); log("Cities inserted."); /** * Select items. */ log("Selecting cities from the table."); const selectItemsStatementCommand = new BatchExecuteStatementCommand({ // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ql-reference.select.html Statements: [ { Statement: `SELECT * FROM ${tableName} WHERE name=?`, Parameters: ["Alachua"], }, { Statement: `SELECT * FROM ${tableName} WHERE name=?`, Parameters: ["High Springs"], }, ], }); const selectItemResponse = await docClient.send(selectItemsStatementCommand); log( `Got cities: ${selectItemResponse.Responses.map( (r) => `${r.Item.name} (${r.Item.population})`, ).join(", ")}`, ); /** * Update items. */ log("Modifying the populations."); const updateItemStatementCommand = new BatchExecuteStatementCommand({ // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ql-reference.update.html Statements: [ { Statement: `UPDATE ${tableName} SET population=? WHERE name=?`, Parameters: [10, "Alachua"], }, { Statement: `UPDATE ${tableName} SET population=? WHERE name=?`, Parameters: [5, "High Springs"], }, ], }); await docClient.send(updateItemStatementCommand); log("Updated cities."); /** * Delete the items. */ log("Deleting the cities."); const deleteItemStatementCommand = new BatchExecuteStatementCommand({ // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ql-reference.delete.html Statements: [ { Statement: `DELETE FROM ${tableName} WHERE name=?`, Parameters: ["Alachua"], }, { Statement: `DELETE FROM ${tableName} WHERE name=?`, Parameters: ["High Springs"], }, ], }); await docClient.send(deleteItemStatementCommand); log("Cities deleted."); /** * Delete the table. */ log("Deleting the table."); const deleteTableCommand = new DeleteTableCommand({ TableName: tableName }); await client.send(deleteTableCommand); log("Table deleted."); };
  • 有关API详细信息,请参阅 “Amazon SDK for JavaScript API参考 BatchExecuteStatement” 中的。

以下代码示例展示了如何:

  • 通过运行SELECT语句获取项目。

  • 通过运行INSERT语句添加项目。

  • 通过运行UPDATE语句更新项目。

  • 通过运行DELETE语句删除项目。

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。查找完整示例,学习如何在 Amazon 代码示例存储库中进行设置和运行。

执行单个 PartiQL 语句。

import { BillingMode, CreateTableCommand, DeleteTableCommand, DescribeTableCommand, DynamoDBClient, waitUntilTableExists, } from "@aws-sdk/client-dynamodb"; import { DynamoDBDocumentClient, ExecuteStatementCommand, } from "@aws-sdk/lib-dynamodb"; import { ScenarioInput } from "@aws-doc-sdk-examples/lib/scenario"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); const log = (msg) => console.log(`[SCENARIO] ${msg}`); const tableName = "SingleOriginCoffees"; export const main = async (confirmAll = false) => { /** * Delete table if it exists. */ try { await client.send(new DescribeTableCommand({ TableName: tableName })); // If no error was thrown, the table exists. const input = new ScenarioInput( "deleteTable", `A table named ${tableName} already exists. If you choose not to delete this table, the scenario cannot continue. Delete it?`, { type: "confirm", confirmAll }, ); const deleteTable = await input.handle({}); if (deleteTable) { await client.send(new DeleteTableCommand({ tableName })); } else { console.warn( "Scenario could not run. Either delete ${tableName} or provide a unique table name.", ); return; } } catch (caught) { if ( caught instanceof Error && caught.name === "ResourceNotFoundException" ) { // Do nothing. This means the table is not there. } else { throw caught; } } /** * Create a table. */ log("Creating a table."); const createTableCommand = new CreateTableCommand({ TableName: tableName, // This example performs a large write to the database. // Set the billing mode to PAY_PER_REQUEST to // avoid throttling the large write. BillingMode: BillingMode.PAY_PER_REQUEST, // Define the attributes that are necessary for the key schema. AttributeDefinitions: [ { AttributeName: "varietal", // 'S' is a data type descriptor that represents a number type. // For a list of all data type descriptors, see the following link. // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Programming.LowLevelAPI.html#Programming.LowLevelAPI.DataTypeDescriptors AttributeType: "S", }, ], // The KeySchema defines the primary key. The primary key can be // a partition key, or a combination of a partition key and a sort key. // Key schema design is important. For more info, see // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/best-practices.html KeySchema: [{ AttributeName: "varietal", KeyType: "HASH" }], }); await client.send(createTableCommand); log(`Table created: ${tableName}.`); /** * Wait until the table is active. */ // This polls with DescribeTableCommand until the requested table is 'ACTIVE'. // You can't write to a table before it's active. log("Waiting for the table to be active."); await waitUntilTableExists({ client }, { TableName: tableName }); log("Table active."); /** * Insert an item. */ log("Inserting a coffee into the table."); const addItemStatementCommand = new ExecuteStatementCommand({ // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ql-reference.insert.html Statement: `INSERT INTO ${tableName} value {'varietal':?, 'profile':?}`, Parameters: ["arabica", ["chocolate", "floral"]], }); await client.send(addItemStatementCommand); log("Coffee inserted."); /** * Select an item. */ log("Selecting the coffee from the table."); const selectItemStatementCommand = new ExecuteStatementCommand({ // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ql-reference.select.html Statement: `SELECT * FROM ${tableName} WHERE varietal=?`, Parameters: ["arabica"], }); const selectItemResponse = await docClient.send(selectItemStatementCommand); log(`Got coffee: ${JSON.stringify(selectItemResponse.Items[0])}`); /** * Update the item. */ log("Add a flavor profile to the coffee."); const updateItemStatementCommand = new ExecuteStatementCommand({ // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ql-reference.update.html Statement: `UPDATE ${tableName} SET profile=list_append(profile, ?) WHERE varietal=?`, Parameters: [["fruity"], "arabica"], }); await client.send(updateItemStatementCommand); log("Updated coffee"); /** * Delete the item. */ log("Deleting the coffee."); const deleteItemStatementCommand = new ExecuteStatementCommand({ // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ql-reference.delete.html Statement: `DELETE FROM ${tableName} WHERE varietal=?`, Parameters: ["arabica"], }); await docClient.send(deleteItemStatementCommand); log("Coffee deleted."); /** * Delete the table. */ log("Deleting the table."); const deleteTableCommand = new DeleteTableCommand({ TableName: tableName }); await client.send(deleteTableCommand); log("Table deleted."); };
  • 有关API详细信息,请参阅 “Amazon SDK for JavaScript API参考 ExecuteStatement” 中的。

以下代码示例显示了如何查询TTL项目。

SDK对于 JavaScript (v3)
import { DynamoDBClient, QueryCommand } from "@aws-sdk/client-dynamodb"; import { marshall, unmarshall } from "@aws-sdk/util-dynamodb"; async function queryDynamoDBItems(tableName, region, primaryKey) { const client = new DynamoDBClient({ region: region, endpoint: `https://dynamodb.${region}.amazonaws.com` }); const currentTime = Math.floor(Date.now() / 1000); const params = { TableName: tableName, KeyConditionExpression: "#pk = :pk", FilterExpression: "#ea > :ea", ExpressionAttributeNames: { "#pk": "primaryKey", "#ea": "expireAt" }, ExpressionAttributeValues: marshall({ ":pk": primaryKey, ":ea": currentTime }) }; try { const { Items } = await client.send(new QueryCommand(params)); Items.forEach(item => { console.log(unmarshall(item)) }); return Items; } catch (err) { console.error(`Error querying items: ${err}`); throw err; } } //enter your own values here queryDynamoDBItems('your-table-name', 'your-partition-key-value');
  • 有关API详细信息,请参阅Amazon SDK for JavaScript API参考中的查询

以下代码示例显示了如何更新项目TTL。

SDK对于 JavaScript (v3)
import { DynamoDBClient, UpdateItemCommand } from "@aws-sdk/client-dynamodb"; import { marshall, unmarshall } from "@aws-sdk/util-dynamodb"; async function updateDynamoDBItem(tableName, region, partitionKey, sortKey) { const client = new DynamoDBClient({ region: region, endpoint: `https://dynamodb.${region}.amazonaws.com` }); const currentTime = Math.floor(Date.now() / 1000); const expireAt = Math.floor((Date.now() + 90 * 24 * 60 * 60 * 1000) / 1000); const params = { TableName: tableName, Key: marshall({ partitionKey: partitionKey, sortKey: sortKey }), UpdateExpression: "SET updatedAt = :c, expireAt = :e", ExpressionAttributeValues: marshall({ ":c": currentTime, ":e": expireAt }), }; try { const data = await client.send(new UpdateItemCommand(params)); const responseData = unmarshall(data.Attributes); console.log("Item updated successfully: %s", responseData); return responseData; } catch (err) { console.error("Error updating item:", err); throw err; } } //enter your values here updateDynamoDBItem('your-table-name', 'us-east-1', 'your-partition-key-value', 'your-sort-key-value');
  • 有关API详细信息,请参阅 “Amazon SDK for JavaScript API参考 UpdateItem” 中的。

无服务器示例

以下代码示例演示如何实现 Lambda 函数,该函数接收通过从 DynamoDB 流接收记录而触发的事件。该函数检索 DynamoDB 有效负载,并记录下记录内容。

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。在无服务器示例存储库中查找完整示例,并了解如何进行设置和运行。

使用 Lambda 使用一个 DynamoDB 事件。 JavaScript

// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. // SPDX-License-Identifier: Apache-2.0 exports.handler = async (event, context) => { console.log(JSON.stringify(event, null, 2)); event.Records.forEach(record => { logDynamoDBRecord(record); }); }; const logDynamoDBRecord = (record) => { console.log(record.eventID); console.log(record.eventName); console.log(`DynamoDB Record: ${JSON.stringify(record.dynamodb)}`); };

使用 Lambda 使用一个 DynamoDB 事件。 TypeScript

export const handler = async (event, context) => { console.log(JSON.stringify(event, null, 2)); event.Records.forEach(record => { logDynamoDBRecord(record); }); } const logDynamoDBRecord = (record) => { console.log(record.eventID); console.log(record.eventName); console.log(`DynamoDB Record: ${JSON.stringify(record.dynamodb)}`); };

以下代码示例演示如何为接收来自 DynamoDB 流的事件的 Lambda 函数实现部分批量响应。该函数在响应中报告批处理项目失败,并指示 Lambda 稍后重试这些消息。

SDK对于 JavaScript (v3)
注意

还有更多相关信息 GitHub。在无服务器示例存储库中查找完整示例,并了解如何进行设置和运行。

使用 Lambda 报告 DynamoDB 批处理项目失败。 JavaScript

export const handler = async (event) => { const records = event.Records; let curRecordSequenceNumber = ""; for (const record of records) { try { // Process your record curRecordSequenceNumber = record.dynamodb.SequenceNumber; } catch (e) { // Return failed record's sequence number return { batchItemFailures: [{ itemIdentifier: curRecordSequenceNumber }] }; } } return { batchItemFailures: [] }; };

使用 Lambda 报告 DynamoDB 批处理项目失败。 TypeScript

import { DynamoDBBatchResponse, DynamoDBBatchItemFailure, DynamoDBStreamEvent, } from "aws-lambda"; export const handler = async ( event: DynamoDBStreamEvent ): Promise<DynamoDBBatchResponse> => { const batchItemFailures: DynamoDBBatchItemFailure[] = []; let curRecordSequenceNumber; for (const record of event.Records) { curRecordSequenceNumber = record.dynamodb?.SequenceNumber; if (curRecordSequenceNumber) { batchItemFailures.push({ itemIdentifier: curRecordSequenceNumber, }); } } return { batchItemFailures: batchItemFailures }; };