Consider a university database for the scheduling of classrooms for final exams. This database could be modeled as the single entity set exam, with attributes course-name, section-number, room-number, and time. Alternatively, one or more additional entity sets could be defined, along with relationship sets to replace some of the attributes of the exam entity set, as:
course with attributes name, department, and c-number
section with attributes s-number and enrolment, and dependent as a weak entity set on course
room with attributes r-number, capacity, and building
This is an ER diagram example that illustrates the use of all three additional entity sets listed.
