[ignoramous]

When you require point and range queries. For example, given a cart-id, fetch the skus; given a authz-token, fetch scopes; given a user-id and a time-range, fetch a list of pending order-ids.

There's a lot more you could do though, DynamoDB, is after all, a wide-column KV store. Ref this re:invent talk from 2018: https://www.youtube-nocookie.com/embed/HaEPXoXVf2k

Apart from being fully-managed, the key selling points of DynamoDB are its consistent performance for a given query type, read-your-writes consistency semantics, auto-replication, auto-disaster recovery.

See also: https://martinfowler.com/bliki/AggregateOrientedDatabase.htm... (mirror: https://archive.is/lc2eO)

[ramraj07]

The aws reinvent lecture was great and answered exactly when to use dynamodb. I might seriously consider it for some of my applications for sure.