The figure 1and figure 2 represents an EER model used design database for the country club. Figure 1 indicates one superclass and two subclasses. A club member is a superclass while a social member and golf member are the two specialized subclasses. According to the figure, a social member and golf member subclasses are overlapping because golf club enjoys social member privileges, meaning golf member is also a social member.
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Each member uses one or more privileges in his or her membership type. That means the degree of relationship between club member and privileges is binary (degree of 2), and cardinality is many-to-many (n:m).