Cardinality constraint analyse and implementation in access control model

Analysis the concept of constraints and diversity of security access control model. According to actual demand, we describe the user-role, user-session, role-session cardinality constraints of the ANSI RBAC model. The differences between static and dynamic cardinality constraints are also represented particularly. An extended model is established including cardinality constraints. In order to support the extended model, some management and query functions are added and modified in implementation.