In Amazon DynamoDB, partition keys and sort keys are key components of the primary key structure used to uniquely identify items within a table. Understanding these concepts is crucial for designing efficient data models and optimizing query performance.
Partition Key :
* A partition key, also known as a hash key, is a single attribute chosen as the primary key for a DynamoDB table.
* DynamoDB uses the partition key's value to partition the data across multiple partitions for storage and retrieval.
* Each item in the table is stored in a partition determined by the hash value of its partition key.
* Partition keys are essential for achieving scalability and distributing workload evenly across partitions.
* Items with the same partition key value are stored together in the same partition, allowing for efficient retrieval of all items with the same partition key.
Sort Key (also known as Range Key in previous DynamoDB documentation) :
* A sort key, also known as a range key, is an optional attribute used in combination with the partition key to uniquely identify each item within the table.
* When a sort key is defined, the combination of partition key and sort key values uniquely identifies each item in the table.
* DynamoDB uses the partition key's value to determine the partition in which an item is stored, and the sort key's value to order items within the same partition.
* Sort keys enable range queries, sorting, and efficient querying of data based on various criteria.
* Items within the same partition are stored in sort key order, allowing for range queries to retrieve items with sort key values falling within a specified range.
