There is a lot more you should learn about DynamoDB but I appreciate the effort of the author. Please read the AWS documentation, it's not that big and explains vital things that just aren't in this article. Very important things like:

- LSI can't be created after table is created

- GSI late creation generate back pressure on main table

- If you have an LSI, your table will not scale beyond 10GB

- How often a table will scale up and down per day/hour?

- Cost of auto-scaling in cloudwatch (alarms aren't free)

...and so much more. I've been working with Dynamodb for over 2 years now and I love it.