Describe two different ways to represent a birthday register, i.e. the names of your friends and their birth dates. Assume that none of your friends have the same name, but that it is possible for two or more of them to share the same birthday. Do not represent the date as a string. Show how the following data would be represented in both models.
2/Jan Asimov
3/Jan Tolkien
18/July Mandela
18/July Branson