Document client abstraction in DynamoDB - Mini Project: Build & Apply

Document Client Abstraction with DynamoDB

📖 Scenario: You are building a simple inventory system for a small store. You want to store product information in a DynamoDB table using a document client abstraction to make it easier to work with the data.

🎯 Goal: Create a DynamoDB document client abstraction that allows you to add, retrieve, and update product items in the inventory table.

📋 What You'll Learn

Create a DynamoDB document client instance

Define a table name variable

Write a function to add a product item to the table

Write a function to get a product item by its ID

Write a function to update the quantity of a product item

💡 Why This Matters

🌍 Real World

This abstraction simplifies working with DynamoDB in real applications like inventory management, user profiles, or any document-based data storage.

💼 Career

Understanding how to use DynamoDB DocumentClient and write clean data access functions is valuable for backend developers working with AWS services.

1

Create DynamoDB Document Client and Table Name

Create a variable called docClient that initializes a new DynamoDB DocumentClient instance. Also create a variable called tableName and set it to the string 'Inventory'.

DynamoDB

# Your code here

Need a hint?

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

2

Write Function to Add a Product Item

Write an async function called addProduct that takes a parameter product. Inside the function, create a variable params with TableName set to tableName and Item set to product. Use await docClient.put(params).promise() to add the item.

DynamoDB

const AWS = require('aws-sdk');
const docClient = new AWS.DynamoDB.DocumentClient();
const tableName = 'Inventory';

// Your code here

Need a hint?

Use docClient.put with params and call promise() to await the operation.

3

Write Function to Get a Product by ID

Write an async function called getProductById that takes a parameter productId. Inside the function, create a variable params with TableName set to tableName and Key set to an object with id equal to productId. Use const result = await docClient.get(params).promise() and return result.Item.

DynamoDB

const AWS = require('aws-sdk');
const docClient = new AWS.DynamoDB.DocumentClient();
const tableName = 'Inventory';

async function addProduct(product) {
    const params = {
        TableName: tableName,
        Item: product
    };
    await docClient.put(params).promise();
}

// Your code here

Need a hint?

Use docClient.get with params and return the Item from the result.

4

Write Function to Update Product Quantity

Write an async function called updateProductQuantity that takes parameters productId and newQuantity. Inside the function, create a variable params with TableName set to tableName, Key set to an object with id equal to productId, UpdateExpression set to 'set quantity = :q', ExpressionAttributeValues set to an object with :q equal to newQuantity, and ReturnValues set to 'UPDATED_NEW'. Use await docClient.update(params).promise() to perform the update.

DynamoDB

const AWS = require('aws-sdk');
const docClient = new AWS.DynamoDB.DocumentClient();
const tableName = 'Inventory';

async function addProduct(product) {
    const params = {
        TableName: tableName,
        Item: product
    };
    await docClient.put(params).promise();
}

async function getProductById(productId) {
    const params = {
        TableName: tableName,
        Key: { id: productId }
    };
    const result = await docClient.get(params).promise();
    return result.Item;
}

// Your code here

Need a hint?

Use docClient.update with the correct parameters to update the quantity attribute.