Basic scan operation in DynamoDB - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does a scan operation do in DynamoDB?

A scan operation reads every item in a DynamoDB table and returns all data attributes by default.

beginner

How is a scan different from a query in DynamoDB?

Scan reads the whole table without filtering by key, while query finds items using the primary key or indexes.

beginner

What is a common downside of using a scan operation?

Scan can be slow and costly because it reads every item, even if you only need a few.

intermediate

How can you limit the data returned by a scan?

You can use a filter expression to return only items that match certain conditions after scanning.

intermediate

What parameter controls how many items a scan returns at once?

The Limit parameter sets the maximum number of items returned in one scan call.

What does a DynamoDB scan operation do?

A Reads every item in the table

B Reads items by primary key only

C Deletes items from the table

D Updates items in the table

A scan reads every item in the table, unlike a query which reads by key.

Which parameter limits the number of items returned in a scan?

A FilterExpression

B Limit

C KeyConditionExpression

D ProjectionExpression

The Limit parameter controls how many items are returned in one scan call.

Why might using scan be inefficient?

A It requires a primary key

B It only reads indexed attributes

C It reads the entire table even if not needed

D It deletes data accidentally

Scan reads the whole table, which can be slow and costly if the table is large.

How can you reduce the data returned by a scan?

A Use a query instead

B Use a delete operation

C Use a batch write

D Use a filter expression

Filter expressions let you return only items that meet certain conditions after scanning.

Which operation is better for retrieving items by primary key?

A Query

B Scan

C PutItem

D UpdateItem

Query is designed to efficiently retrieve items by primary key.

Explain what a basic scan operation does in DynamoDB and when you might use it.

Think about reading every page in a book to find information.

Describe how you can control the amount of data returned by a scan operation.

Imagine filtering a big list after looking at all items.