AWS Database Services
Domain 3: Cloud Technology and Services — Task 3.4: Identify AWS database services
This chapter introduces the wide range of database technologies available in AWS. Because AWS offers purpose-built databases for nearly every workload, the Cloud Practitioner exam focuses on whether you can match the right database service to a specific use case and understand when managed services are preferable to self-managed databases on EC2.
Understanding AWS Database Options
AWS provides relational, NoSQL, in-memory, and specialized databases, each optimized for different types of data and performance needs. A key concept on the exam is the difference between running databases on EC2, where the customer manages everything, and using AWS managed database services, where AWS handles patching, backups, scaling, and availability.
The exam also emphasizes how AWS supports database modernization and migration through built-in tools.
Relational Databases
Relational databases are best for structured data, strong consistency, and transactional workloads. AWS provides fully managed relational services such as Amazon RDS and Amazon Aurora that automatically handle backups, patching, and high availability.
Exam Tip: When a question mentions automated maintenance, scaling, or high availability, the correct answer is RDS or Aurora—not a database running on EC2.
NoSQL Databases
For applications that require flexible schemas, massive scale, and low latency, AWS offers NoSQL options. Amazon DynamoDB is a serverless key-value and document store designed for high-performance workloads and global replication. Amazon DocumentDB supports MongoDB-compatible document databases.
Exam Tip: If the scenario requires low-latency access at scale or global replication, DynamoDB is the correct choice.
In-Memory Databases
In-memory databases are designed for extremely fast access to frequently used data. Amazon ElastiCache supports Redis and Memcached for caching, session storage, and real-time analytics. Amazon MemoryDB for Redis provides Redis compatibility with built-in durability and fault tolerance.
Exam Tip: When a question focuses on reducing database load or accelerating application performance, ElastiCache is the correct service.
Specialized Databases
AWS also offers databases built for specific data models. Amazon Neptune is used for graph workloads such as fraud detection and social networks. Amazon Timestream stores time-series data for IoT and monitoring applications. Amazon QLDB provides an immutable ledger for tracking financial or legal records.
These services are designed to solve problems that traditional relational databases handle poorly.
Database Migration Tools
AWS provides managed tools to move and modernize databases. AWS Database Migration Service (DMS) supports continuous replication and low-downtime migrations. AWS Schema Conversion Tool (SCT) converts schemas and code when moving between different database engines.
Exam Tip: Minimal-downtime migrations use DMS. Engine and schema conversion uses SCT.
EC2-Hosted vs. Managed Databases
When databases run on EC2, the customer is responsible for patching, scaling, backups, and availability. With managed services such as RDS, Aurora, and DynamoDB, AWS handles infrastructure, maintenance, and scaling automatically.
Exam Tip: If the question asks how to reduce operational overhead or improve reliability, choose an AWS managed database service.
Example: Migrating Oracle to Aurora
A common modernization scenario involves moving an on-premises Oracle database to Amazon Aurora. AWS SCT converts the Oracle schema into a PostgreSQL-compatible format. AWS DMS then migrates the live data with minimal downtime. Aurora is deployed in a Multi-AZ configuration to provide high availability.
This approach shows how AWS database services and migration tools work together.
Key Exam Reminders
Use RDS or Aurora for relational workloads. Use DynamoDB for high-scale NoSQL. Use ElastiCache for in-memory caching and MemoryDB for durable Redis. Use Neptune for graph data, Timestream for time-series data, and QLDB for immutable ledgers. DMS handles live data migration, while SCT handles schema conversion. Managed services always reduce operational effort compared to EC2-hosted databases.
Final Thoughts
AWS offers purpose-built databases for every type of workload. On the exam, your job is to identify whether the scenario calls for a relational, NoSQL, in-memory, or specialized database and then select the AWS service that best fits that need. Remember that managed services simplify operations and that migration tools like DMS and SCT enable smooth modernization. Mastering these relationships ensures you can choose the right database solution in any exam scenario or real-world architecture.
