Database Table Design

Im trying to design a database to use in SQL server , the design i've got now is working but It just doesn't look right to me and there must be a better way to set things out.





Heres the current situation





Theres 3 tables





USERTYPES





USERS





TICKETS





The users table holds the user information i.e.





userID


userName


Phone Number


userTypeID *





It contains a foreign key called userTypeID which is a primary key of USERTYPES





The USERTYPES table contains the two types of users on the system , these are standard and admin, so the table looks like this.








USERTYPESID


typeName





The TICKETS table holds the ticket details of tickets submitted by users. so





ticketID


ticketName


ticketDescription


DueDate


ticketRequestor *


AssignedTo *





Now here is where I have the problem, the ticketRequestor is a foreign key of the STAFF table staffID however AssignedTo is also a foreign key of the STAFF table staffID.





Currently in order to get this working i've had to turn off the enforce relationship for the AssignedTO - staffID link but idealy I think this enforce relationship should be on to ensure its a truely relational.





any ideas as to what I need to do to organise the relationships better ?





thanks