How to make an access database where both users with and without an ID number can make a transaction -

I am trying to create an Access 2007 database that already has an ID number and other guests to make a transaction. Allows the user who does not have an ID number, do transactions. What is the best way to use it? One transaction involves taking one item out of the list. So if any user (employee or external) has an item out of the list then no other user can hold that item, thanks, any thoughts would be appreciated most!

assuming that you had a table of users with the primary key, I just got a "guest in this table. "The user will setup. Then assuming that your inventory table has a claim called "bookautobi", you will enter only this guest user id and normal user id for everyone else in that field.

Many assumptions but you did not give us many specials to go!