Alternative Forms

• Number of Role Members

• Role Members Number

Definitions

Definition 1

The number of members in a role at time t.

Examples

Roles were so numerous and their cardinality was so low, Alice thought: “this is characteristic of a role explosion“.

Related Terms

Quotes

Quotes

2.3 Role authorization

The association of a user with a role can be subject to the following:

(…)
• the numerical limitation that exists for role membership cannot be exceeded.

(…)

The third property listed above which can be preserved under the granting of user membership to roles is the Cardinality property. Some roles can only be occupied by a certain number of employees at any given period of time. For example, consider the role of Manager. Although other employees may act in that role, only one employee may assume the responsibilities of a manager at any given time. A user can become a new member of a role as long as the number of members allowed for the role is not exceeded. The number of users allowed for a role and the existing number of users associated with a role is specified by the following two functions:

membership-limit (r: roles) = the membership limit ( ≥ 0) for role “r.” (eq. 11)

number-of-members(r:roles) = N ( ≥ 0) the number of existing members in role “r.” (eq. 12)

Role capacity can now be described as:

Rule 3 (Cardinality) The capacity of a role cannot be exceeded by an additional role member:

∀ r :roles :

membership-limit(r) ≥ number-of-members(r). (eq. 13)

Bibliography

• Ferraiolo, 1995

See Also