search for: pay_type_id

I''m try to verify users on login. Here is my code: def self.authenticate(username,password,account_code) employee = self.find(:all, :select => "e.id, e.first_name, e.last_name, e.username, e.account_id, e.department_id, o.pay_type_id, o.admin_yn, o.payroll_yn, o.files_yn, o.dept_report_yn,e.salt, e.hashed_password", :conditions => ["e.deleted_yn=0 and e.username = ? and a.account_code = ?", username, account_code], :joins => "as e left outer join options o on e.id = o.employee_id left outer...

Heya everyone! I am quite new to Rails and I am reading AWDwR. I am at Task E "Check Out!". I understand it quite well, but I have a problem with the last playground exercise: Add a Table which contains the payment types. All goes well, but I am not sure whether I should use has_many or has_one(as in the Playground wiki at http://wiki.pragprog.com/cgi-bin/wiki.cgi/PT-E-3). I use the