Understanding item collections
It is likely that not all access patterns for an application would only deal with a single item all the time. Several access patterns for a modern application could require fetching multiple items related to each other in some manner. Like a simple key value acting in a singleton manner, items having the same partition key could have different sort key values, such that for each item, the partition key and sort key combination remains unique across the table data.
A group of items having the same partition key value but different sort key values is called an item collection. An example of an item collection would be maintaining the version history of all mutations performed for a user item or a game state object. If I were to allow my users to request a history of all mutations for their profile, I would store the profile data in such a way where the partition key for the item collection is user_id and the sort key could be an epoch timestamp or ISO...
