Both. UUIDs require much less storage/memory than string keys, and you can create offline bulk inserts quickly and easily with them. Make your table with UUID

Both. UUIDs require much less storage/memory than string keys, and you can create offline bulk inserts quickly and easily with them. Make your table with UUIDs as the primary keys, and then create a unique, human-readable lookup key as an additional column. This gives you the best of both worlds.