Final answer:
In RBAC design, the Cardinality constraint specifies the number of roles a user can be assigned, ensuring that policies limiting user roles are enforced.
Step-by-step explanation:
In Role-Based Access Control (RBAC) design, the type of constraint that specifies the number of roles a user can be assigned is known as a Cardinality constraint. Different types of constraints in RBAC ensure that access rights are properly managed and consistent with organizational policies.
The Cardinality constraint is particularly important for limiting the assignment of roles to users, thus enforcing policies that might, for example, limit users to having only one or a few specific roles within a system to prevent conflicts of interest or excessive privileges.
Other constraints like Separation of duty constraints ensure that conflicting roles are not assigned to the same user, while Inclusion constraints and Temporal constraints may govern how roles relate to each other and when roles can be activated, respectively.