CLF-C02 - Cloud Technology and Services (34% of the exam) - Section 3.6

Identify AWS database services, distinguishing relational databases such as Amazon RDS and Amazon Aurora from NoSQL databases such as Amazon DynamoDB and memory-based databases.

Distinguish relational database services - Amazon RDS for standard SQL engines and Amazon Aurora for a cloud-native, high-performance relational database - from NoSQL options. Recognise Amazon DynamoDB as a fully managed key-value and document NoSQL database suited to high-throughput, low-latency workloads, and identify memory-based caching services as a separate category.

Amazon RDSAmazon AuroraAmazon DynamoDBManaged databases

Practice question for this objective

Free sampleCloud Technology and Servicesmedium

A team is reviewing the AWS database portfolio and must identify which services are relational databases that organise data into tables queried with SQL. Which TWO of the following AWS services are relational databases? (Select TWO.)

  • AAmazon RDS, a managed service that runs relational engines such as MySQL and PostgreSQL using tables and SQL. Correct
  • BAmazon DynamoDB, a fully managed database that stores items as flexible key-value and document records.
  • CAmazon Aurora, a relational database built by AWS that is compatible with MySQL and PostgreSQL tables and SQL. Correct
  • DAmazon ElastiCache, a managed in-memory data store that keeps data in RAM for very low-latency caching.
  • EAmazon S3, a managed object store that holds files as objects in buckets reached through a URL.
Amazon RDS and Amazon Aurora are AWS relational databases that organise data into tables queried with SQL, unlike NoSQL, in-memory, or object stores. A relational database arranges data into related tables and answers SQL queries with joins and transactions. Both Amazon RDS and Amazon Aurora run relational engines such as MySQL and PostgreSQL on this model, whereas DynamoDB is NoSQL key-value, ElastiCache keeps data in memory for caching, and Amazon S3 holds objects in buckets, none of which are relational.

Why A is correct: Amazon RDS hosts relational engines whose data lives in tables queried with SQL, so it belongs in the relational category.

Why B is wrong: DynamoDB is a NoSQL key-value and document store, so it is tempting alongside the others but is not a relational database.

Why C is correct: Aurora is a relational engine compatible with MySQL and PostgreSQL, so its table-based SQL data makes it relational.

Why D is wrong: ElastiCache is an in-memory caching store rather than a table-based SQL database, so it is not relational.

Why E is wrong: Amazon S3 stores unstructured objects in buckets, not tables queried with SQL, so it is object storage and not a database.

See more CLF-C02 practice questions, answers explained.

Exam traps in Cloud Technology and Services

Answers that look right on this material and are not. Each one is a distractor from a different question in the CLF-C02 bank for this domain.

  • Amazon DynamoDB and Amazon Aurora are relational databases, while Amazon RDS is a NoSQL database

    Why it is wrong: This swaps the categories incorrectly, because DynamoDB is NoSQL rather than relational and RDS is a relational service rather than a NoSQL store.

  • Amazon DynamoDB, a fully managed database that stores items as key-value records without a fixed table schema.

    Why it is wrong: DynamoDB is managed but it is a NoSQL key-value store, not a relational database, so it does not fit this relational requirement.

  • Amazon RDS for MySQL, a managed relational database that organises data into fixed tables joined by SQL queries

    Why it is wrong: RDS is tempting because it is a managed database, but it stores data in fixed relational tables with a defined schema, which does not suit records whose attributes vary widely from item to item.

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