When we design a table in a relational database, we think about normalization. We aim for 3NF (Third Normal Form), join relationships with foreign keys, and combine data with JOINs. DynamoDB overturns all of these assumptions. There are no JOINs. Transactions are limited. The schema isn't fixed. In exchange, it guarantees single-digit millisecond response times across hundreds of millions of items.
Amazon built an internal system called Dynamo in 2004, to store shopping cart data. Not a single request could be lost at peak traffic