AWS Certified Developer – Associate — All Questions

When designing a DynamoDB table, why is choosing a high-cardinality partition key important?

• a.It distributes reads and writes evenly and avoids hot partitions✓
• b.It reduces the cost per gigabyte stored
• c.It enables strongly consistent reads automatically
• d.It removes the need for a sort key

A high-cardinality partition key spreads traffic across many partitions, preventing a single hot partition that would throttle. It does not change storage pricing, does not set consistency (which is chosen per request), and is unrelated to whether a sort key is needed.

A developer must query a DynamoDB table by an attribute that is not the primary key. What should they create?

• a.A DynamoDB Stream
• b.A second table copied nightly
• c.A global secondary index on that attribute✓
• d.A CloudFront distribution

A global secondary index lets you query on a non-key attribute efficiently. Streams emit change events, a nightly copy would be stale and costly, and CloudFront is a content delivery network unrelated to querying items.

An application must guarantee it reads the most recent write immediately after updating an item in DynamoDB. What should it request?

• a.A Scan operation
• b.A strongly consistent read✓
• c.A global secondary index query
• d.A batch write

By default DynamoDB reads are eventually consistent; requesting a strongly consistent read returns the latest committed data. A Scan reads the whole table, a GSI is only eventually consistent, and batch writes are for writing, not reading.

A developer wants separate dev and prod configurations for the same API Gateway API without redeploying different code. Which feature supports this?

• a.A single stage for all environments
• b.Hard-coded backend URLs
• c.One API per environment only
• d.Stages with stage variables✓

API Gateway stages represent deployments such as dev and prod, and stage variables parameterize integrations (for example pointing to different Lambda aliases) without code changes. A single stage or hard-coded URLs cannot separate environments cleanly, and creating entirely separate APIs is unnecessary duplication.