Global Secondary Index (GSI) concept in DynamoDB - Mini Project: Build & Apply

Create and Query a Global Secondary Index (GSI) in DynamoDB

📖 Scenario: You are building a simple product catalog database using DynamoDB. You want to store products with their ProductID as the main key. Later, you want to quickly find products by their Category using a Global Secondary Index (GSI).

🎯 Goal: Create a DynamoDB table with a primary key ProductID, add a Global Secondary Index (GSI) on Category, and write a query to find all products in a specific category.

📋 What You'll Learn

Create a DynamoDB table named Products with ProductID as the partition key.

Add a Global Secondary Index named CategoryIndex with Category as the partition key.

Insert sample product items with ProductID, Name, and Category attributes.

Write a query using the GSI CategoryIndex to find all products in the category Electronics.

💡 Why This Matters

🌍 Real World

Global Secondary Indexes let you query DynamoDB tables efficiently by attributes other than the primary key, which is common in real-world applications like product catalogs, user profiles, and event logs.

💼 Career

Understanding GSIs is essential for database engineers and backend developers working with DynamoDB to design scalable and performant NoSQL databases.

1

Create the DynamoDB table with primary key

Create a DynamoDB table named Products with ProductID as the partition key of type S (string). Use the AWS CLI command aws dynamodb create-table with the required attributes and key schema.

DynamoDB

# Use aws dynamodb create-table with TableName 'Products' and KeySchema with 'ProductID' as HASH
# Your code here

Need a hint?

Use the AWS CLI create-table command with --attribute-definitions and --key-schema options.

2

Add a Global Secondary Index (GSI) on Category

Update the Products table creation command to include a Global Secondary Index named CategoryIndex with Category as the partition key of type S. Add --attribute-definitions for Category and define the GSI with --global-secondary-indexes.

DynamoDB

aws dynamodb create-table \
    --table-name Products \
    --attribute-definitions AttributeName=ProductID,AttributeType=S AttributeName=Category,AttributeType=S \
    --key-schema AttributeName=ProductID,KeyType=HASH \
    --global-secondary-indexes IndexName=CategoryIndex,KeySchema=[{AttributeName=Category,KeyType=HASH}],Projection={ProjectionType=ALL},ProvisionedThroughput={ReadCapacityUnits=5,WriteCapacityUnits=5} \
    --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5
# Your code here

Need a hint?

Remember to add Category to --attribute-definitions and define the GSI with --global-secondary-indexes.

3

Insert sample product items

Insert three product items into the Products table using the AWS CLI put-item command. Use these exact items:
1. {"ProductID": {"S": "P100"}, "Name": {"S": "Smartphone"}, "Category": {"S": "Electronics"}}
2. {"ProductID": {"S": "P101"}, "Name": {"S": "Laptop"}, "Category": {"S": "Electronics"}}
3. {"ProductID": {"S": "P102"}, "Name": {"S": "Coffee Mug"}, "Category": {"S": "Kitchen"}}

DynamoDB

aws dynamodb put-item --table-name Products --item '{"ProductID": {"S": "P100"}, "Name": {"S": "Smartphone"}, "Category": {"S": "Electronics"}}'
# Add two more put-item commands for the other products

Need a hint?

Use aws dynamodb put-item three times with the exact JSON items.

4

Query products by Category using the GSI

Write an AWS CLI query command to find all products in the Electronics category using the Global Secondary Index CategoryIndex. Use --table-name Products, --index-name CategoryIndex, and a KeyConditionExpression with Category = :cat. Define the expression attribute value :cat as {"S": "Electronics"}.

DynamoDB

# Write the aws dynamodb query command here to find products in Electronics category using CategoryIndex
# Your code here

Need a hint?

Use aws dynamodb query with --index-name CategoryIndex and the correct key condition expression.