I want to create an inventory system for an online multiplayer game, so I was thinking about database.
My research led me to this form:
id (user, bigint, unsigned + index, foreign key for user's id in users table)
itemid (item_id, int, unsigned)
amount (amount of the items, int)
I know there will be a lot of rows with duplicated user IDs - are there any improvements I can make to this design to work with that?