Membership hierarchy

Users and organizational entities within the Member subsystem are organized into a hierarchy. Generally this hierarchy mimics a typical organizational hierarchy, with entries for organizations and organizational units, and entries for users in the leaf nodes. The hierarchy includes artificial organizational entities created specifically to support access control. The entries in the hierarchy are as follows:

Note that an organizational entity is typically an organization, such as "IBM", whereas an organizational unit is within an organization, such as "Electronic Commerce Division". 

The MBRREL table stores membership hierarchy information, and must be populated for every user and organizational entity. The MBRREL table only contains entries for registered users. Guest users always have the Default Organization as their parent organizational entity. The members that are above a user or organizational entity in the membership hierarchy are referred to as the ancestors of that user or organizational entity. The immediate ancestor is also referred to as the parent.