i will have 10-12 tables in my database and each will have its own user table. one of my tables is a membership file and only users who are in this table can be granted permissions in any table. several questions:

1. i don't want a Name field in each user table. however, i would like to display the name from the membership table where this field is displayed. how do i look up the real name from the membership table? (the username in the membership table will match the username in each user table)

2. when i create a new user in any user table, i would like to validate the username against the membership table.