Reference Book: Fundamentals of Database Management Systems Consider the Grade R

Question

Reference Book: Fundamentals of Database Management Systems

Consider the Grade Report Relation with the composite Primary Key: Student_ Id and Course _Id. Note each course is taught by one Instructor and each Instructor has one Instructor_ Location. An Instructor teaches at least one course. Similarly, each student has one Address and one Major. List the functional dependencies in this relation. For this relation, identify each of the following: an insert anomaly, a delete anomaly, and a modification anomaly. In what normal form is this relation? Develop a set of 3NF relations from this relation and show them in an entity relationship diagram. Grade Report:

Explanation / Answer

Hi,

Please find below the answers-

Ans a)
{Student_Id,Course_Id}-->Student_Name
{Student_Id,Course_Id}-->Address
{Student_Id,Course_Id}-->Major
{Student_Id,Course_Id}-->Course_Title
{Student_Id,Course_Id}-->Instructor_name
{Student_Id,Course_Id}-->Instructor_Location
{Student_Id,Course_Id}-->Grade
Course_Id-->Course_Title
Course_Id-->Instructor_name
Course_Id-->Instructor_Location
Student_Id-->Student_Name
Student_Id-->Address
Student_Id-->Major
Student_Id-->Grade
Instructor_name-->Instructor_Location

Ans b) Ans b) Insertion anamoly-
Suppose a new course has been added into the School. Then it cannot be added to this table untill and unless a student enrolls for it. Because, if the couse is added and no student has enrolled in it then there will be a null value in the student_id column of this table which is not alowed as student_id is primary key.
Deletion anamoly-
Suppose,some of the student leaves the school. Then that particular row will be deleted from the table. But if we delete entire row, the corresponding course to which student was enrolled will also get deleted.
Updation Anamoly-
Suppose the instructor location has changed, then the same information has to be updated in all the rows of the table and not just one row.

Ans c) This relation is in First Normal form.

Explantion- This is because if we consider {Student_id,course_id} as primary key, then we can see that the column course_title can be determined by course_id alone and it does not depend on student_id at all. In other words we can say that the attribute is partially dependent on the candidate key which is against second normal form.

Ans d) Below are the third normal form relations-

Student(Student_id,Student_name,Address,Major,Course_id,Grade)

Course(Course_id,Course_title,instructor_name)

Instructor(instructor_name,instructor_location)

Thanks and Regards,

Vinay Singh

Related Questions

Navigate

• Browse (All)
• Browse R
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.