1. Construct an object model for a library. The library has an aggregation relationship with book and with patron. That is, the library is really made up of books and patrons. The relationship between book and copy is neither aggregation nor inheritance. The object book represents the abstraction of a book, while the copy is the physical item that is loaned out. The relationship between patron and copy is called ‘‘loan.'' From the view of copy, the role is ‘‘checked out by'' and from patron the role is ‘‘checkout.'' The multiplicities indicate that a copy can either not be checked out or can have this relationship with only one patron at a time (‘‘0.1''). The other multiplicity, ‘‘0.*'', indicates that a patron can have zero or one or many relationships of ‘‘checkout'' at a time.
2. Construct an object model for a family-tree system that stores genealogical information about family members. Every marriage has a father person and a mother person. Many attributes have been left off the diagram, and no functions are shown.