Understanding Permission Lists
Permission lists are the building blocks of user security authorizations. You typically create permission lists before you create user profiles and roles. When defining permission lists, however, consider the roles and user profiles with which you will use them. Recall that roles are intermediary objects between permission lists and users. You use roles to assign permissions to users dynamically.
Permission lists may contain any number of permissions, such as sign in times, page permissions, web services permissions, and so on. Permission lists are more flexible and scalable when they contain fewer permissions.
Image: Security definitions hierarchy showing how permissions flow to roles, which flow to user profiles
The following diagram illustrates how permission lists are assigned to roles, which are then assigned to user profiles. A role may contain numerous permissions, and a user profile may have numerous roles assigned to it. A user inherits all permissions assigned to each role to which the user belongs. User access is determined by the combination of all assigned roles.
The diagram represents the security authorizations of Tom Sawyer. Mr. Sawyer inherits the five permission lists that are assigned to the two roles that are assigned to his user profile. In this example, he has access to the employee self-service pages, the service monitor, PeopleSoft Process Monitor, and PeopleTools Security. If Tom were to become a manager, then the permission lists assigned to the Manager role would be added to his profile.
Theoretically, you could create a permission list tailored for every role, and that permission list could contain a permission for every category, from General to Web Libraries. However, permission lists like this do not scale to encompass roles that might be similar but not exactly alike. For a similar role, you would have to create a new role from the beginning. This kind of approach is not efficient for larger, more complicated implementations.
Alternatively, you can use a more modular, or mix-and-match, approach whereby you create numerous, generic permission lists that you can add to and remove from role definitions. Suppose you have three 8-hour shifts at your site. Using the modular approach, you could create three different versions of sign in permissions: one for 6 a.m. to 2 p.m., one for 2 p.m. to 10 p.m., and another for 10 p.m. to 6 a.m. Then, depending on the shift for a particular role, you can easily apply or remove the appropriate permission as needed without affecting any other permissions.
Although how you decide to implement Permission Lists depends on your site's security scheme and your security administrator, the modular approach provides increased scalability. As a general rule, your permission lists should be assigned to roles so that the common user has between 10 to 20 lists. This range represents the best balance of performance and flexibility. If you have too many permission lists, you may notice performance degradation, and if you have too few permission lists, you may sacrifice flexibility.