Partitions and data distribution

Amazon DynamoDB scales horizontally (using data partition/sharding) and can seamlessly scale a single table over hundreds of servers.
DynamoDB is schemaless.
When you create a table in DynamoDB, you specify only the primary key attributes, such as partition key or partition key and sort key. You do not define any other attributes in advance.

Key Concepts

Concept	Description
Partition	A partition is an allocation of storage for a table, backed by solid state drives (SSDs) and automatically replicated across multiple Availability Zones within an AWS Region.
Partition key	DynamoDB uses the value of the partition key as input to an internal hash function. - Hence it must be specified in both read and write operations.
Primary Key	When you create a table, in addition to the table name, you must specify the primary key of the table. - The primary key uniquely identifies each item in the table, so that no two items can have the same key.

Primary Key type	Description
⭐ Composite Primary Key - Partition key and sort key	All items with the same partition key value are stored together, in sorted order by sort key value. - This helps in querying items more efficiently.
Partition key only	We can only use partition key as primary key (must be specified in both read and write operations).