A primary key uniquely identifies each item in the table, so no

two items can have the same key. DynamoDB supports two

different kinds of primary keys:

▪ Partition key

▪ Partition key and sort key

▪ Partition key

A simple primary key, composed of one attribute known as the

partition key.

▪ Partition key and Sort Key

It is Referred to as a composite primary key, this type of key is

composed of two attributes. The first attribute is the partition

key, and the second attribute is the sort key.

▪ DynamoDB uses the partition key value as input to an internal

hash function. A composite primary key gives you additional

flexibility when querying data

https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/HowItWorks.CoreComponents.html