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Reading and Writing Items in Batch in DynamoDB

This Node.js code example shows:

The Scenario

In this example, you use a series of Node.js modules to put a batch of items in a DynamoDB table as well as read a batch of items. The code uses the SDK for JavaScript to perform batch read and write operations using these methods of the DynamoDB client class:

Prerequisite Tasks

To set up and run this example, first complete these tasks:

Reading Items in Batch

Create a Node.js module with the file name ddb_batchgetitem.js. Be sure to configure the SDK as previously shown. To access DynamoDB, create an AWS.DynamoDB service object. Create a JSON object containing the parameters needed to get a batch of items, which in this example includes the name of one or more tables from which to read, the values of keys to read in each table, and the projection expression that specifies the attributes to return. Call the batchGetItem method of the DynamoDB service object.

// 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);
    });
  }
});

To run the example, type the following at the command line.

node ddb_batchgetitem.js

This sample code can be found here on GitHub.

Writing Items in Batch

Create a Node.js module with the file name ddb_batchwriteitem.js. Be sure to configure the SDK as previously shown. To access DynamoDB, create an AWS.DynamoDB service object. Create a JSON object containing the parameters needed to get a batch of items, which in this example includes the table into which you want to write items, the key(s) you want to write for each item, and the attributes along with their values. Call the batchWriteItem method of the DynamoDB service object.

// 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);
  }
});

To run the example, type the following at the command line.

node ddb_batchwriteitem.js

This sample code can be found here on GitHub.