It occurs to me that I could still use integer primary keys internally and have indexed strings as external lookup keys. I want the same key to be able to show

It occurs to me that I could still use integer primary keys internally and have indexed strings as external lookup keys. I want the same key to be able to show (a) which user, (b) which database, and (c) which row, so I can verify ownership and route directly to the particular sub-db without having to do several lookups first.