PutItem (creating items) in DynamoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to put an item into the DynamoDB table.

DynamoDB

response = table.[1](Item={'UserId': '123', 'Name': 'Alice'})

Drag options to blanks, or click blank then click option'

Aget_item

Bdelete_item

Cput_item

Dupdate_item

Attempts:

3 left

💡 Hint

Common Mistakes

Using get_item instead of put_item will only retrieve data, not create it.

Using delete_item will remove an item, not add one.

The put_item method is used to create or replace an item in a DynamoDB table.

2fill in blank

medium

Complete the code to specify the table name when creating a DynamoDB resource.

DynamoDB

table = dynamodb.Table('[1]')

Drag options to blanks, or click blank then click option'

AUserTable

Bput_item

CItem

D123

Attempts:

3 left

💡 Hint

Common Mistakes

Using method names or keywords instead of the actual table name.

Using numbers instead of the table name string.

The table name must be a string matching the DynamoDB table you want to access.

3fill in blank

hard

Fix the error in the code to correctly put an item with a numeric attribute.

DynamoDB

response = table.put_item(Item={'UserId': '123', 'Age': [1])

Drag options to blanks, or click blank then click option'

A25

B'twenty-five'

C'25'

D"25"

Attempts:

3 left

💡 Hint

Common Mistakes

Passing numbers as strings causes DynamoDB to treat them as strings.

Using words instead of numeric values.

Numeric attributes in DynamoDB should be passed as numbers, not strings.

4fill in blank

hard

Fill both blanks to put an item with a string and a list attribute.

DynamoDB

response = table.put_item(Item={'UserId': '[1]', 'Tags': [2])

Drag options to blanks, or click blank then click option'

Auser123

B['tag1', 'tag2']

D['tag1', tag2]

Attempts:

3 left

💡 Hint

Common Mistakes

Not quoting the UserId string.

Using invalid list syntax for Tags.

The UserId is a string, so it needs quotes. The Tags attribute is a list of strings, represented as a Python list literal.

5fill in blank

hard

Fill all three blanks to put an item with a nested map attribute.

DynamoDB

response = table.put_item(Item={'UserId': '[1]', 'Profile': [2], 'Active': [3])

Drag options to blanks, or click blank then click option'

Auser456

B{'Name': 'Bob', 'Age': 30}

CTrue

DFalse

Attempts:

3 left

💡 Hint

Common Mistakes

Not using quotes for UserId string.

Using incorrect syntax for the nested map.

Using string 'true' instead of boolean True.

UserId is a string, Profile is a nested dictionary (map), and Active is a boolean value.

Practice

1. What does the PutItem operation do in DynamoDB?

easy

A. Reads an item from a table

B. Deletes an item from a table

C. Updates only specific attributes of an item

D. Adds a new item or replaces an existing item in a table

Solution

1. Step 1: Understand the purpose of PutItem

   PutItem is used to add a new item or replace an existing item in a DynamoDB table.

2. Step 2: Compare with other operations

   Delete removes items, Get reads items, and Update modifies specific attributes, so they differ from PutItem.

3. Final Answer:

   Adds a new item or replaces an existing item in a table -> Option D

4. Quick Check:

   PutItem = Add or replace item [OK]

Hint: PutItem adds or replaces whole items, not partial updates [OK]

Common Mistakes:

• Confusing PutItem with UpdateItem
• Thinking PutItem only adds without replacing
• Mixing PutItem with Delete or Get operations

2. Which of the following is the correct syntax snippet to add an item with PutItem in DynamoDB using AWS SDK?

easy

A. dynamodb.putItem({ TableName: 'Users', Item: { 'UserId': { S: '123' }, 'Name': { S: 'Alice' } } })

B. dynamodb.put({ Table: 'Users', Item: { UserId: '123', Name: 'Alice' } })

C. dynamodb.insertItem({ TableName: 'Users', Item: { 'UserId': '123', 'Name': 'Alice' } })

D. dynamodb.addItem({ TableName: 'Users', Item: { 'UserId': { N: 123 }, 'Name': { S: 'Alice' } } })

Solution

1. Step 1: Check the correct method and parameters

   The AWS SDK method is putItem with parameters TableName and Item where each attribute has a type like S for string.

2. Step 2: Validate the attribute format

   dynamodb.putItem({ TableName: 'Users', Item: { 'UserId': { S: '123' }, 'Name': { S: 'Alice' } } }) uses the correct method and attribute typing. Other options use wrong method names or omit types.

3. Final Answer:

   dynamodb.putItem({ TableName: 'Users', Item: { 'UserId': { S: '123' }, 'Name': { S: 'Alice' } } }) -> Option A

4. Quick Check:

   Correct method and typed attributes = dynamodb.putItem({ TableName: 'Users', Item: { 'UserId': { S: '123' }, 'Name': { S: 'Alice' } } }) [OK]

Hint: Use putItem with typed attributes like { S: 'value' } [OK]

Common Mistakes:

• Using wrong method names like put or insertItem
• Not specifying attribute types (S, N, etc.)
• Using wrong parameter names like Table instead of TableName

3. Given the following PutItem request, what will be the result in the DynamoDB table?

{
  TableName: 'Products',
  Item: {
    'ProductId': { S: 'p100' },
    'Name': { S: 'Pen' },
    'Price': { N: '5' }
  }
}

medium

A. An error occurs because Price is a number but given as a string

B. Only the ProductId attribute is saved, others are ignored

C. A new item with ProductId 'p100', Name 'Pen', and Price 5 is added or replaced

D. The item is added but Price is stored as a string, not number

Solution

1. Step 1: Understand attribute types in PutItem

   In DynamoDB, number attributes are passed as strings inside the N type, so '5' is valid for number.

2. Step 2: Result of PutItem operation

   The item with all specified attributes is added or replaces existing item with same ProductId.

3. Final Answer:

   A new item with ProductId 'p100', Name 'Pen', and Price 5 is added or replaced -> Option C

4. Quick Check:

   PutItem stores typed attributes correctly = A new item with ProductId 'p100', Name 'Pen', and Price 5 is added or replaced [OK]

Hint: Number values are strings inside N type in PutItem [OK]

Common Mistakes:

• Thinking number values must be numeric type, not string
• Assuming partial attributes are saved
• Confusing attribute types and values

4. You try to run this PutItem request but get an error:

{
  TableName: 'Orders',
  Item: {
    'OrderId': 'o123',
    'Amount': { N: '100' }
  }
}

What is the likely cause of the error?

medium

A. The table name 'Orders' is invalid

B. The attribute 'OrderId' is missing its type wrapper like { S: 'o123' }

C. The number value '100' should be a number, not a string

D. The Item object must be an array, not an object

Solution

1. Step 1: Check attribute format in Item

   Each attribute must specify its type, e.g., { S: 'value' } for strings. Here, 'OrderId' lacks the type wrapper.

2. Step 2: Validate other parts

   TableName is valid, number values are strings inside N, and Item is an object, so those are correct.

3. Final Answer:

   The attribute 'OrderId' is missing its type wrapper like { S: 'o123' } -> Option B

4. Quick Check:

   All attributes need type wrappers = The attribute 'OrderId' is missing its type wrapper like { S: 'o123' } [OK]

Hint: Always wrap attributes with type like { S: 'text' } or { N: '123' } [OK]

Common Mistakes:

• Omitting type wrappers for string attributes
• Confusing number values as numeric instead of string
• Assuming Item can be an array

5. You want to add a new user item with UserId as the primary key and optional Age attribute only if it is provided (not null). Which PutItem approach correctly handles this conditional attribute?

hard

A. Include Age in the Item only if it is not null, otherwise omit it

B. Always include Age with value { N: '0' } if null

C. Set Age to an empty string { S: '' } when null

D. Use PutItem with a condition expression to skip Age attribute

Solution

1. Step 1: Understand optional attribute handling

   In DynamoDB PutItem, you include only attributes you want saved. Omitting optional attributes if null is correct.

2. Step 2: Evaluate other options

   Setting Age to zero or empty string changes data meaning. Condition expressions control item existence, not attribute presence.

3. Final Answer:

   Include Age in the Item only if it is not null, otherwise omit it -> Option A

4. Quick Check:

   Omit null attributes to avoid wrong data = Include Age in the Item only if it is not null, otherwise omit it [OK]

Hint: Only add attributes if they have real values, omit nulls [OK]

Common Mistakes:

• Adding attributes with zero or empty string instead of omitting
• Misusing condition expressions for attribute presence
• Assuming PutItem auto-skips null attributes