With Role Based Access Control (RBAC), each role is associated with a set of operations which a user in that role may perform. The power of RBAC as an access control mechanism is the concept that an operation may theoretically be anything. This is contrasted to other access control mechanisms where bits or labels are associated with information blocks. These bits or labels indicate relatively simple operations, such as, read or write, which can be performed on an information block. Operations in RBAC may be arbitrarily complex, e.g., 'a night surgical nurse can only append surgical information to a patient record from a workstation in the operating theater while on duty in that operating theater from midnight to 8 AM.' A goal for implementing RBAC is to allow operations associated with roles to be as general as possible while not adversely impacting the administrative flexibility or the behavior of applications.