Problem
Draw the Entity Relationship Diagram (ERD) as explained below, showing both the minimum and maximum cardinality in both directions using Crows Foot notation. Also, be sure to identify the relationship.
1. Glockville University is divided into several schools: business, arts and sciences, education, and applied sciences. Each SCHOOL is administered by a dean who is a PROFESSOR. Each professor can be the dean of only one school and a professor is not required to be the dean of any school.
2. Each school comprises several departments. For example, the school of business has an accounting department, a management/marketing department, an economics/finance department, and a computer information systems department. The smallest number of departments operated by a school is one, and the large number of departments in many (indeterminate). On the other hand, each DEPARTMENT belongs to only a single school. That is, the minimum number of schools to which a department belongs is one, as is the maximum number.
3. Each department may offer courses. For example, the management/marketing department offers courses such as Introduction to Management, Principles of Marketing, and Production Management. If Glockville University had some departments that were classified as "research only" they would not offer courses; therefore, the COURSE entity would be optional to the DEPARTMENT entity.
4. A CLASS is a section of a COURSE. That is, a department may offer several sections (classes) of the same database course. Each of those classes is taught by a professor at a given time in a given place. CLASS is optional to COURSE.
5. Each department should have one or more professors assigned to it. One and only one of those professors chairs the department, and no professor is required to accept the chair position. Therefore, DEPARTMENT is optional to PROFESSOR in the "chairs" relationship.
6. Each professor may teach up to four classes; each class is a section of a course. A professor may also be on a research contract and teach no classes at all.