DynamoDB

It’s a NoSQL Database from AWS

Differences from SQL Database

Records of a table can have different fields
Tables can be partitioned using partition keys, I think you cannot query fast across different partitions. I think an analogy to partition keys would be like having a table across multiple databases in SQL Databases
Tables also have sort keys, this determines how records are ordered, and you can only query contiguous records, I think you cannot filter nor change the order (maybe only reverse the default order)
So basically partition keys and sort keys determines how the table can be queried. This limitations is the tradeoff that makes DynamoDB fast.
There are some advantages with the connection management, I think it allows a lot more concurrent connections, but I don’t know the details.

High scalability
Better integration with serverless architecture, because of better connection management