Why CRUD operations are foundational in DynamoDB - See It in Action

Why CRUD Operations Are Foundational in DynamoDB

📖 Scenario: You are building a simple contact list app that stores people's names and phone numbers using DynamoDB. You want to learn how to add, read, update, and delete contacts in your database.

🎯 Goal: Build a basic DynamoDB table and practice the four main CRUD operations: Create, Read, Update, and Delete contacts.

📋 What You'll Learn

Create a DynamoDB table named Contacts with ContactID as the primary key.

Add a new contact with a specific ContactID, Name, and PhoneNumber.

Read a contact's details by ContactID.

Update the PhoneNumber of an existing contact.

Delete a contact by ContactID.

💡 Why This Matters

🌍 Real World

Managing contacts, products, or any data records in apps requires CRUD operations to keep data accurate and up to date.

💼 Career

Understanding CRUD in DynamoDB is essential for backend developers, database administrators, and cloud engineers working with AWS services.

1

Create the DynamoDB table and add a contact

Create a DynamoDB table named Contacts with ContactID as the primary key. Then add a contact with ContactID set to "1", Name set to "Alice", and PhoneNumber set to "123-456-7890".

DynamoDB

# Your code here to create the table and add the contact

Need a hint?

Use boto3.resource('dynamodb') to connect. Create the table with ContactID as the HASH key. Use put_item to add the contact.

2

Set up a variable to hold the contact ID to read

Create a variable called contact_id and set it to the string "1". This will be used to read the contact details.

DynamoDB

import boto3

dynamodb = boto3.resource('dynamodb')

# Create the Contacts table
contacts_table = dynamodb.create_table(
    TableName='Contacts',
    KeySchema=[{'AttributeName': 'ContactID', 'KeyType': 'HASH'}],
    AttributeDefinitions=[{'AttributeName': 'ContactID', 'AttributeType': 'S'}],
    ProvisionedThroughput={'ReadCapacityUnits': 5, 'WriteCapacityUnits': 5}
)

contacts_table.wait_until_exists()

# Add a contact
contacts_table.put_item(Item={'ContactID': '1', 'Name': 'Alice', 'PhoneNumber': '123-456-7890'})

# Create a variable to hold the contact ID to read
# Your code here

Need a hint?

Just create a variable named contact_id and assign it the string '1'.

3

Read the contact details using the contact ID

Use the get_item method on contacts_table to get the contact with ContactID equal to the variable contact_id. Store the result in a variable called response.

DynamoDB

import boto3

dynamodb = boto3.resource('dynamodb')

# Create the Contacts table
contacts_table = dynamodb.create_table(
    TableName='Contacts',
    KeySchema=[{'AttributeName': 'ContactID', 'KeyType': 'HASH'}],
    AttributeDefinitions=[{'AttributeName': 'ContactID', 'AttributeType': 'S'}],
    ProvisionedThroughput={'ReadCapacityUnits': 5, 'WriteCapacityUnits': 5}
)

contacts_table.wait_until_exists()

# Add a contact
contacts_table.put_item(Item={'ContactID': '1', 'Name': 'Alice', 'PhoneNumber': '123-456-7890'})

# Create a variable to hold the contact ID to read
contact_id = '1'

# Use get_item to read the contact
# Your code here

Need a hint?

Use contacts_table.get_item(Key={'ContactID': contact_id}) and assign it to response.

4

Update the contact's phone number and then delete the contact

Use the update_item method on contacts_table to change the PhoneNumber of the contact with ContactID equal to contact_id to "987-654-3210". Then use the delete_item method to remove the contact with ContactID equal to contact_id.

DynamoDB

import boto3

dynamodb = boto3.resource('dynamodb')

# Create the Contacts table
contacts_table = dynamodb.create_table(
    TableName='Contacts',
    KeySchema=[{'AttributeName': 'ContactID', 'KeyType': 'HASH'}],
    AttributeDefinitions=[{'AttributeName': 'ContactID', 'AttributeType': 'S'}],
    ProvisionedThroughput={'ReadCapacityUnits': 5, 'WriteCapacityUnits': 5}
)

contacts_table.wait_until_exists()

# Add a contact
contacts_table.put_item(Item={'ContactID': '1', 'Name': 'Alice', 'PhoneNumber': '123-456-7890'})

# Create a variable to hold the contact ID to read
contact_id = '1'

# Use get_item to read the contact
response = contacts_table.get_item(Key={'ContactID': contact_id})

# Update the phone number and delete the contact
# Your code here

Need a hint?

Use update_item with UpdateExpression to change the phone number. Then use delete_item with the key to remove the contact.