Pagination with SDK in DynamoDB - Mini Project: Build & Apply

Pagination with SDK

📖 Scenario: You are building a simple application that fetches user data from a DynamoDB table called Users. The table contains many user records, and you want to retrieve them in small chunks (pages) to avoid loading too much data at once.

🎯 Goal: Learn how to use the DynamoDB SDK to fetch user records with pagination, retrieving one page of results at a time.

📋 What You'll Learn

Create a DynamoDB client using the AWS SDK

Set a page size limit for the number of items to fetch

Write a query or scan operation that fetches one page of user data

Use the pagination token to fetch the next page of results

💡 Why This Matters

🌍 Real World

Pagination is essential when working with large datasets in DynamoDB to avoid loading too much data at once and to improve performance and user experience.

💼 Career

Understanding how to paginate DynamoDB results is a common task for backend developers and cloud engineers working with AWS services.

1

Create DynamoDB client

Create a DynamoDB client called dynamodb using new AWS.DynamoDB.DocumentClient().

DynamoDB

# Create a DynamoDB client
# Your code here

Need a hint?

Use new AWS.DynamoDB.DocumentClient() to create the client.

2

Set page size limit

Create a variable called pageSize and set it to 5 to limit the number of items fetched per page.

DynamoDB

const AWS = require('aws-sdk');
const dynamodb = new AWS.DynamoDB.DocumentClient();

// Set the page size limit
# Your code here

Need a hint?

Set pageSize to 5 to fetch 5 items per page.

3

Fetch one page of users

Write a params object with TableName set to 'Users' and Limit set to pageSize. Then call dynamodb.scan(params).promise() and assign the result to data using await.

DynamoDB

const AWS = require('aws-sdk');
const dynamodb = new AWS.DynamoDB.DocumentClient();

const pageSize = 5;

// Fetch one page of users
# Your code here

Need a hint?

Use scan with Limit to get a page of items.

4

Use pagination token for next page

Add ExclusiveStartKey to params using a variable called lastKey. After fetching data, update lastKey with data.LastEvaluatedKey to prepare for the next page.

DynamoDB

const AWS = require('aws-sdk');
const dynamodb = new AWS.DynamoDB.DocumentClient();

const pageSize = 5;

let lastKey = undefined;

const params = {
    TableName: 'Users',
    Limit: pageSize
};

async function fetchPage() {
    // Add ExclusiveStartKey if lastKey exists
    # Your code here

    const data = await dynamodb.scan(params).promise();

    // Update lastKey with LastEvaluatedKey
    # Your code here

    return data;
}

Need a hint?

Use ExclusiveStartKey to continue from the last page.