Makes a single 1 to many relationship into many 1 to 1 relationships, by distinguishing each association by a qualifier id. This will then make it possible to identify an object uniquely by giving the qualifier id of the association. Can subset the objects at many end into groups each group being associated to a qualifying group id at the 1 end. This converts a 1 to many relationship into many 1 to many relationships. In the figure example, figure id will identify a unique figure or a group of figures depending on whether the qualifier is for each object or each group of objects.