Attribute types (S, N, B, BOOL, L, M) in DynamoDB - Mini Project: Build & Apply

Working with DynamoDB Attribute Types

📖 Scenario: You are building a simple inventory system using DynamoDB. Each item in the inventory has different types of attributes like strings, numbers, booleans, lists, and maps.

🎯 Goal: Create a DynamoDB item using various attribute types: S (string), N (number), B (binary), BOOL (boolean), L (list), and M (map).

📋 What You'll Learn

Create a DynamoDB item dictionary named item with specific attributes.

Add a configuration variable binary_data to hold binary content.

Use the correct DynamoDB attribute types for each attribute in item.

Complete the item with all required attributes using the correct DynamoDB data types.

💡 Why This Matters

🌍 Real World

DynamoDB is widely used for fast, scalable NoSQL databases in web and mobile applications. Understanding attribute types is essential for storing and retrieving data correctly.

💼 Career

Many cloud and backend developer roles require working with DynamoDB or similar NoSQL databases. Knowing how to structure data with correct attribute types is a key skill.

1

Create the initial DynamoDB item with string and number attributes

Create a dictionary called item with two attributes: "ProductName" as a string with value "Coffee Mug" and "Price" as a number with value 12.99. Use DynamoDB attribute types S for string and N for number.

DynamoDB

# Your code here

Hint

Remember, DynamoDB numbers are stored as strings inside the N attribute.

2

Add a binary attribute configuration

Create a variable called binary_data and assign it the byte string b'\x01\x02\x03' to represent binary data.

DynamoDB

item = {
    "ProductName": {"S": "Coffee Mug"},
    "Price": {"N": "12.99"}
}
# Your code here

Hint

Use the b'' syntax to create a byte string in Python.

3

Add boolean, binary, list, and map attributes to the item

Add these attributes to the item dictionary: "InStock" as a boolean True using BOOL, "Image" as binary using B with the variable binary_data, "Tags" as a list L containing two strings "Ceramic" and "Kitchen", and "Dimensions" as a map M with keys "Height" and "Width" having number values 4 and 3 respectively.

DynamoDB

item = {
    "ProductName": {"S": "Coffee Mug"},
    "Price": {"N": "12.99"}
}
binary_data = b'\x01\x02\x03'
# Your code here

Hint

Lists use L with a list of attribute dictionaries. Maps use M with a dictionary of attribute dictionaries.

4

Complete the DynamoDB item with all attributes

Ensure the item dictionary includes all attributes: ProductName (string), Price (number), InStock (boolean), Image (binary), Tags (list of strings), and Dimensions (map with height and width numbers). The variable binary_data should be defined as b'\x01\x02\x03'.

DynamoDB

item = {
    "ProductName": {"S": "Coffee Mug"},
    "Price": {"N": "12.99"},
    "InStock": {"BOOL": True},
    "Image": {"B": binary_data},
    "Tags": {"L": [{"S": "Ceramic"}, {"S": "Kitchen"}]},
    "Dimensions": {"M": {
        "Height": {"N": "4"},
        "Width": {"N": "3"}
    }}
}
binary_data = b'\x01\x02\x03'
# Your code here

Hint

Review all attribute types and ensure the dictionary is complete and correctly formatted.

Practice

1.

Which DynamoDB attribute type is used to store plain text strings?

easy

A. B

B. N

C. BOOL

D. S

Solution

1. Step 1: Understand attribute types in DynamoDB

   DynamoDB uses attribute types to define data kinds. 'S' stands for string (text).

2. Step 2: Match the type to text data

   Since 'S' means string, it is the correct type for plain text.

3. Final Answer:

   S -> Option D

4. Quick Check:

   Text data = S [OK]

Hint: Text data always uses type S in DynamoDB [OK]

Common Mistakes:

• Confusing N (number) with S (string)
• Choosing BOOL for text
• Using B for text data

2.

Which of the following is the correct syntax to define a boolean attribute named isActive in a DynamoDB item?

{"isActive": {"BOOL": true}}

easy

A. {"isActive": {"S": "true"}}

B. {"isActive": {"BOOL": true}}

C. {"isActive": {"N": 1}}

D. {"isActive": {"B": true}}

Solution

1. Step 1: Identify the correct attribute type for boolean

   Boolean values in DynamoDB use the BOOL type with true or false.

2. Step 2: Check the syntax for boolean attribute

   The correct syntax is {"isActive": {"BOOL": true}} to represent a boolean true.

3. Final Answer:

   {"isActive": {"BOOL": true}} -> Option B

4. Quick Check:

   Boolean attribute uses BOOL type [OK]

Hint: Use BOOL type with true/false for boolean values [OK]

Common Mistakes:

• Using S type with string 'true'
• Using N type with 1 instead of BOOL
• Using B type for boolean

3.

Given the following DynamoDB item attribute, what is the type of tags?

{"tags": {"L": [ {"S": "red"}, {"S": "blue"}, {"S": "green"} ] }}

medium

A. List (L)

B. Map (M)

C. String (S)

D. Binary (B)

Solution

1. Step 1: Identify the attribute type key

   The attribute uses the key "L", which stands for List in DynamoDB.

2. Step 2: Understand the value structure

   The value is an array of strings, confirming it is a list of string elements.

3. Final Answer:

   List (L) -> Option A

4. Quick Check:

   Attribute key L means List [OK]

Hint: Look for L key to identify lists in DynamoDB [OK]

Common Mistakes:

• Confusing L with M (map)
• Thinking it's a string because of S inside list
• Choosing B for binary data

4.

Identify the error in this DynamoDB attribute definition:

{"profile": {"M": {"age": {"S": 30}, "name": {"S": "Alice"}}}}

medium

A. The name attribute should use type N, not S

B. The map (M) type cannot contain nested attributes

C. The age attribute should use type N, not S

D. Binary (B) type is missing for profile

Solution

1. Step 1: Analyze the attribute types inside the map

   The map contains "age" with type S and value 30, and "name" with type S and value "Alice".

2. Step 2: Check if types match values

   Age is a number (30), so it should use type N, not S (string). Name is correctly a string.

3. Final Answer:

   Age attribute should use type N, not S -> Option C

4. Quick Check:

   Numbers use N type, not S [OK]

Hint: Numbers inside maps must use N type, not S [OK]

Common Mistakes:

• Using S for numbers
• Thinking maps can't nest attributes
• Confusing name type as number

5.

You want to store a user's profile with a list of phone numbers and a map of address details in DynamoDB. Which attribute types should you use for phoneNumbers and address respectively?

hard

A. phoneNumbers: L, address: M

B. phoneNumbers: M, address: L

C. phoneNumbers: S, address: B

D. phoneNumbers: BOOL, address: N

Solution

1. Step 1: Identify the type for a list of phone numbers

   A list of phone numbers is a collection, so it should use the List (L) type.

2. Step 2: Identify the type for address details as key-value pairs

   Address details are structured data with keys and values, so Map (M) type is appropriate.

3. Final Answer:

   phoneNumbers: L, address: M -> Option A

4. Quick Check:

   Lists = L, Maps = M [OK]

Hint: Use L for lists, M for maps (objects) in DynamoDB [OK]

Common Mistakes:

• Swapping L and M types
• Using S for lists
• Using BOOL or N incorrectly