TTL attribute setup in DynamoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the TTL attribute name in DynamoDB.

DynamoDB

table.update_time_to_live({
  TTLSpecification: {
    Enabled: true,
    AttributeName: "[1]"
  }
})

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

AexpirationTime

BexpireAt

Cttl

DdeleteAt

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different attribute name than the one storing the expiration timestamp.

Forgetting to enable TTL in the specification.

The TTL attribute name must match the attribute you use to store the expiration timestamp. Commonly, it is named ttl.

2fill in blank

medium

Complete the code to enable TTL on the DynamoDB table.

DynamoDB

table.update_time_to_live({
  TTLSpecification: {
    Enabled: [1],
    AttributeName: "ttl"
  }
})

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

A1

Bfalse

C"true"

Dtrue

Attempts:

3 left

💡 Hint

Common Mistakes

Using string "true" instead of boolean true.

Setting Enabled to false disables TTL.

TTL must be enabled by setting Enabled to the boolean true, not a string or number.

3fill in blank

hard

Fix the error in the TTL setup code by completing the missing part.

DynamoDB

const params = {
  TableName: "MyTable",
  [1]: {
    Enabled: true,
    AttributeName: "ttl"
  }
};

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

ATimeToLiveSpec

BTimeToLiveSpecification

CTTLSpecification

DTTLSpec

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect parameter names like TTLSpecification or TTLSpec.

Misspelling or wrong casing of the parameter name.

The correct parameter name for TTL setup in AWS SDK is TimeToLiveSpecification.

4fill in blank

hard

Fill both blanks to correctly configure TTL in the AWS SDK call.

DynamoDB

const params = {
  TableName: "Orders",
  [1]: {
    Enabled: [2],
    AttributeName: "expireAt"
  }
};

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

ATimeToLiveSpecification

Btrue

Cfalse

DTTLSpecification

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong parameter name.

Setting Enabled to false disables TTL.

Use TimeToLiveSpecification as the parameter name and set Enabled to true to activate TTL.

5fill in blank

hard

Fill all three blanks to create a TTL update request with correct keys and values.

DynamoDB

const ttlParams = {
  [1]: "Products",
  [2]: {
    Enabled: [3],
    AttributeName: "deletionTime"
  }
};

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

ATableName

BTimeToLiveSpecification

Ctrue

DTTLSpecification

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up the keys or using incorrect names.

Setting Enabled to false disables TTL.

The TableName key specifies the table, TimeToLiveSpecification holds TTL settings, and Enabled must be true to enable TTL.

Practice

1. What is the main purpose of setting a TTL attribute in a DynamoDB table?

easy

A. To increase the read capacity of the table

B. To encrypt data stored in the table

C. To create backups of the table data

D. To automatically delete expired items based on a timestamp

Solution

1. Step 1: Understand TTL functionality

   TTL (Time To Live) is used to automatically remove items after a certain time.

2. Step 2: Identify the purpose in DynamoDB context

   In DynamoDB, TTL deletes expired items to save storage and cost.

3. Final Answer:

   To automatically delete expired items based on a timestamp -> Option D

4. Quick Check:

   TTL = auto-delete expired items [OK]

Hint: TTL means auto-delete expired data by timestamp [OK]

Common Mistakes:

• Confusing TTL with encryption
• Thinking TTL increases capacity
• Assuming TTL creates backups

2. Which of the following is the correct way to specify the TTL attribute in DynamoDB?

easy

A. Set a numeric attribute with Unix epoch time in seconds

B. Set a list attribute with expiration dates

C. Set a boolean attribute to true when item expires

D. Set a string attribute with date format 'YYYY-MM-DD'

Solution

1. Step 1: Recall TTL attribute data type

   DynamoDB TTL requires a numeric attribute representing Unix epoch time in seconds.

2. Step 2: Evaluate options

   Only Set a numeric attribute with Unix epoch time in seconds correctly uses numeric Unix epoch seconds for TTL.

3. Final Answer:

   Set a numeric attribute with Unix epoch time in seconds -> Option A

4. Quick Check:

   TTL attribute = numeric Unix epoch seconds [OK]

Hint: TTL attribute must be numeric Unix epoch seconds [OK]

Common Mistakes:

• Using string date formats instead of numeric
• Using boolean or list types for TTL
• Not enabling TTL on the table after setting attribute

3. Given a DynamoDB item with attribute expireAt set to 1700000000 (Unix epoch seconds), and TTL enabled on expireAt, what happens when the current time is 1700000001?

medium

A. The item remains until manually deleted

B. The item is automatically deleted by DynamoDB

C. The item is archived automatically

D. The item is updated with a new TTL value

Solution

1. Step 1: Understand TTL expiration behavior

   When current time exceeds the TTL timestamp, DynamoDB marks the item for deletion.

2. Step 2: Apply to given timestamp

   Since current time 1700000001 > expireAt 1700000000, item is deleted automatically.

3. Final Answer:

   The item is automatically deleted by DynamoDB -> Option B

4. Quick Check:

   Current time > TTL timestamp = item deleted [OK]

Hint: Item deletes when current time passes TTL timestamp [OK]

Common Mistakes:

• Thinking item stays until manual deletion
• Assuming item is archived instead of deleted
• Believing TTL updates item automatically

4. You set the TTL attribute to a string value like "2024-12-31" and enabled TTL on that attribute. What issue will you face?

medium

A. TTL will not delete expired items because attribute is not numeric

B. DynamoDB will throw a syntax error on enabling TTL

C. Items will be deleted immediately regardless of date

D. TTL will convert string to numeric automatically

Solution

1. Step 1: Check TTL attribute type requirement

   TTL attribute must be numeric Unix epoch seconds, not string.

2. Step 2: Analyze effect of string value

   DynamoDB ignores TTL deletion if attribute is not numeric, so items won't expire.

3. Final Answer:

   TTL will not delete expired items because attribute is not numeric -> Option A

4. Quick Check:

   Non-numeric TTL attribute = no deletion [OK]

Hint: TTL attribute must be numeric; strings cause no deletion [OK]

Common Mistakes:

• Expecting DynamoDB to error on TTL enable
• Assuming immediate deletion with wrong type
• Believing automatic type conversion happens

5. You want to set up TTL on a DynamoDB table to delete items 7 days after creation. Which approach correctly sets the TTL attribute expireAt when inserting an item?

hard

A. Set expireAt to a boolean true after 7 days

B. Set expireAt to current date string plus 7 days in 'YYYY-MM-DD' format

C. Set expireAt to current Unix epoch seconds plus 604800 (7 days in seconds)

D. Set expireAt to the current Unix epoch seconds without adding days

Solution

1. Step 1: Calculate TTL timestamp for 7 days later

   7 days = 7 * 24 * 60 * 60 = 604800 seconds; add to current Unix epoch seconds.

2. Step 2: Set TTL attribute correctly

   Assign expireAt the numeric value of current time + 604800 seconds for proper TTL.

3. Final Answer:

   Set expireAt to current Unix epoch seconds plus 604800 (7 days in seconds) -> Option C

4. Quick Check:

   TTL timestamp = now + 7 days in seconds [OK]

Hint: Add 604800 seconds to now for 7-day TTL [OK]

Common Mistakes:

• Using date strings instead of numeric timestamps
• Setting TTL to current time without delay
• Using boolean or other types for TTL