Millennium College wants you to help design a star schema to record grades for courses completed by students. There are four dimension tables, with attributes as follows:
CourseSection……………………..Attributes: CourselD, SectionNumber, CourseName, Units,
RoomID, and RoomCapacity. During a given semester, the college offers an average of 500 course sections.
Professor…………………………….Attributes: ProfID, ProfName, Title,
DepartmentID, and DepartmentName. There are typically 200 professors at Millennium at any given time.
Student………………………………Attributes: StudentID, StudentName, and
Major. Each course section has an average of 40 students, and students typically take five courses per period.
Period……………………………….Attributes: SemesterlD and Year. The
database will contain data for 30 periods (a total of 10 years).
The only fact that is to be recorded in the fact table is CourseGrade.
a. Design a star schema for this problem. See Figure 9-10 for the format you should follow.
b. Estimate the number of rows in the fact table, using the assumptions stated previously.
c. Estimate the total size of the fact table (in bytes), assuming that each field has an average of 5 bytes.
d. If you didn't want to or didn't have to stick with a strict star schema for this data mart, how would you change the design? Why?
e. Various characteristics of sections, professors, and students change over time. How do you propose designing the star schema to allow for these changes? Why?