This class diagram contains two classes: movie and genre. It shows how a movie (zero or many) contains a genre (one or many). We connect these classes with an association relationship.
Movie enumeration diagram code in Gleek
About class diagrams
Class diagrams are used in software engineering to describe the structure of a system. A class diagram uses Unified Modeling Language (UML) to show the classes, attributes, methods (or operations), and their relationships to each other in the system. Class diagrams prove valuable in object-oriented modeling. Class diagrams can be used to model the data structure or to design a system in detail.