login name Y user name

longin name means the ID you login in the DB.

user name is totally not a name just like login name, 

basic on the "image " user name more like a passpword

 

login name is human, 

DB is a wallet, the user names are VISA card, Masterer carrd, American Express card, Discover card,cash, food stamp,store card, coin

 

on the front door of the store, there are some  sticks to show customer that what card are taking on this store.

that means