[Zope] acl_users and sql

I would like to use the user login from acl_users as a key to search by in an SQL method. How do I call the variable of the particular user logged in? For example, if user 'TestUser' is logged, I want the method to ultimately look like: select * from dummytable where user='TestUser' How do I do this? What is the variable for the user in acl_users folder?