Method for efficiently managing membership in a hierarchical data structure

A method is disclosed to efficiently manage membership within a hierarchical data structure. A record module is included to create a record that includes a member identifier, a member type, and an ancestor list for a member of a hierarchical data structure. The member type identifies the member as resource or a group comprising at least one resource, and the ancestor list comprises group identifiers ordered to represent a hierarchical relationship between the member and a top-level group. A storage module is included that stores the record in a collection. A reference module is included that references the record in response to accessing the member of the hierarchical data structure.