UpdateItem basics in DynamoDB - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the UpdateItem operation in DynamoDB?

The UpdateItem operation modifies existing attributes or adds new attributes to an item in a DynamoDB table without replacing the entire item.

beginner

Which parameter in UpdateItem specifies the changes to be made to an item?

The UpdateExpression parameter defines the attributes to update, add, or remove in the item.

beginner

What does the ExpressionAttributeValues parameter do in an UpdateItem request?

It provides the actual values that are substituted into the UpdateExpression to specify what to update.

intermediate

How can you increment a numeric attribute using UpdateItem?

Use the SET action in the UpdateExpression to increase the numeric attribute by a specified value, e.g., SET attribute = attribute + :val.

intermediate

What happens if you try to update an item that does not exist using UpdateItem?

By default, DynamoDB creates a new item with the specified key and attributes if the item does not exist.

Which parameter in UpdateItem defines the attributes to change?

A Key

B ReturnValues

C UpdateExpression

D ConditionExpression

The UpdateExpression specifies the attributes to update or add.

What does ExpressionAttributeValues provide in an update?

A Values to substitute in the update

B Primary key

C Table name

D Attribute names

It provides the actual values used in the UpdateExpression.

How do you add 5 to a numeric attribute using UpdateItem?

A SET attribute = attribute + 5

B ADD attribute 5

C REMOVE attribute 5

D DELETE attribute 5

You use SET attribute = attribute + :val with :val = 5 in ExpressionAttributeValues.

What does ReturnValues: ALL_NEW do in UpdateItem?

A Returns the item before update

B Returns nothing

C Returns only updated attributes

D Returns the item after update

It returns the entire item as it appears after the update.

If the item does not exist, what does UpdateItem do by default?

A Fails with error

B Creates a new item

C Deletes the item

D Returns null

By default, it creates a new item with the specified key and attributes.

Explain how to use UpdateItem to change an attribute value in DynamoDB.

Think about how you tell DynamoDB what to update and what values to use.

Describe what happens if you update an item that does not exist in DynamoDB using UpdateItem.

Consider the default behavior of UpdateItem when the item is missing.