RDS

Think database + EC2.

Can use SQL (like MySQL, PostgresSQL, Oracle, Microsoft SQL server).

Comes with automatic patching, backups, redundency, failover, and disaster recovery.

Aurora

Amazon's own type of database. It's not MySQL or Postgres, but it quacks like it.

Data is replicated across AZs(?) with 6 copies. 15 read replicas. Continus backups to S3. Point-in-time recovery.

Key-value DB. Think back to the mIRC tables, these are exactly the same.

Also serverless.

Data warehousing/big data. Not serverless.

Move database (sql or not) to AWS.

Development and test migration - You can use DMS to make a copy of production data to dev enviorment to test against without affecting prod.
Consolidation - merge several databases into one.
Continuous replication - send ongoing copies to other targets.

Source and target are the same type.

Source and target are of different types.

Need to be converted using the conversion tool. Will change the schema and code to match target.
Use DMS to target.

Think content management system.

Graphing database. Who is connected to who kind. For social networking and recomendations and fraud detection.

Think financial actions tracking. Any entry can never be removed.

For blockchains.

In memory database.

Caching for DynamoDB.