That would cause problems when users are renamed. You want foreign keys (which Arango doesn't have?) and transactions, and you also want to make sure that every

That would cause problems when users are renamed. You want foreign keys (which Arango doesn't have?) and transactions, and you also want to make sure that every name change updates all foreign tables. Changing it one place eliminates all possible mistakes, which is why surrogate keys were invented. The way I like to approach performance issues like these is to cache or precompute de normalized data as needed, and make sure the master data is as clean and normalized as possible. You could have a materialized view, or a trigger that produced the denormalized version, or just store the data is Memcached.