Idempotency tokens in DynamoDB - Mini Project: Build & Apply

Idempotency Tokens with DynamoDB

📖 Scenario: You are building an online order system where customers can submit orders. Sometimes, customers might accidentally send the same order twice due to network issues. To prevent creating duplicate orders, you will use idempotency tokens stored in a DynamoDB table.

🎯 Goal: Create a DynamoDB table to store orders with an idempotency_token as the primary key. Then, write a query to check if an order with a given idempotency_token already exists before adding a new order.

📋 What You'll Learn

Create a DynamoDB table named Orders with idempotency_token as the partition key.

Add a sample order item with a specific idempotency_token and order details.

Create a variable called token_to_check with the idempotency token value to search.

Write a query to check if an order with token_to_check exists in the Orders table.

💡 Why This Matters

🌍 Real World

Idempotency tokens help prevent duplicate processing of the same request in systems like online ordering, payment processing, and API calls.

💼 Career

Understanding idempotency tokens and how to use them with DynamoDB is important for backend developers and database engineers working on reliable and fault-tolerant systems.

1

Create the DynamoDB table with idempotency_token as the primary key

Create a DynamoDB table named Orders with idempotency_token as the partition key of type String.

DynamoDB

# Your code here to create the Orders table with idempotency_token as partition key

Need a hint?

Use CREATE TABLE Orders and define idempotency_token as the primary key of type STRING.

2

Add a sample order item with an idempotency token

Insert an order item into the Orders table with idempotency_token set to 'token123', order_id as 'order001', customer_name as 'Alice', and order_amount as 100.

DynamoDB

CREATE TABLE Orders (
  idempotency_token STRING PRIMARY KEY,
  order_id STRING,
  customer_name STRING,
  order_amount NUMBER
);

# Your code here to insert a sample order with idempotency_token 'token123'

Need a hint?

Use INSERT INTO Orders with the exact values for idempotency_token, order_id, customer_name, and order_amount.

3

Create a variable for the idempotency token to check

Create a variable called token_to_check and set it to the string 'token123' to represent the idempotency token you want to search for.

DynamoDB

CREATE TABLE Orders (
  idempotency_token STRING PRIMARY KEY,
  order_id STRING,
  customer_name STRING,
  order_amount NUMBER
);

INSERT INTO Orders (idempotency_token, order_id, customer_name, order_amount) VALUES ('token123', 'order001', 'Alice', 100);

# Your code here to create token_to_check variable with value 'token123'

Need a hint?

Define token_to_check as a string variable with the value 'token123'.

4

Write a query to check if the idempotency token exists

Write a SELECT query to find if an order with idempotency_token equal to token_to_check exists in the Orders table.

DynamoDB

CREATE TABLE Orders (
  idempotency_token STRING PRIMARY KEY,
  order_id STRING,
  customer_name STRING,
  order_amount NUMBER
);

INSERT INTO Orders (idempotency_token, order_id, customer_name, order_amount) VALUES ('token123', 'order001', 'Alice', 100);

token_to_check = 'token123'

# Your code here to select orders where idempotency_token equals token_to_check

Need a hint?

Use SELECT * FROM Orders WHERE idempotency_token = 'token123' to check if the token exists.