A central mediating class which records all the one-to-one, one-to-many and many-to-many relationships between a group of selected classes. Classes that use a Relationship Manager to implement their relationship properties and methods have a consistent metaphor and trivial implementation code (one line calls). In contrast - traditional "pointer" and "arraylist" techniques of implementing relationships are fully flexible but often require a reasonable amount of non-trivial code which can be tricky to get working correctly and are almost always a pain to maintain due to the detailed coding and coupling between classes involved.

http://www.andypatterns.com/index.php/design_patterns/relationship_manager/relationship_manager_pattern_-_theory/

Classes that use a Relationship Manager to implement their relationship properties and methods have a consistent metaphor and trivial implementation code (one line calls).

Traditional techniques of implementing relationships are varied and flexible but often require a reasonable amount of non-trivial code which can be tricky to get working correctly and are almost always a pain to maintain due to the detailed coding and coupling between classes involved.

See http://www.andypatterns.com/index.php/design_patterns/relationship_manager for more information and also see the Wiki.