IS520 Exercise #3
Due 02/20/2019
I’ll show the answer in class, so no late assignment accepted!!!
What to do
Base on the information provide, give the highest normal form for the following relations. If it is not possible to determine based on the information provided, then answer “Cannot be determined” is acceptable. If a relation is not in 4NF, split the relation to make the newly formed relations in 4NF. Clearly indicate the key for each relation. A relation given in the form R(A, B) indicates R is the name of the relation, A and B are attributes of the relation, and A (being underlined) is the key of the relation. Remember if A is the key of a relation and B is a non-key attribute, we always have A B implied. This is also true when the key is a composite key.
The relations are:
R (A, B, C) and C B. A real example of this could be Bad_Enrollment (SID, ClassName, CRN), where SID is column A, CRN is column C, and ClassName is column B).
R (A, B, C), C B, and A + C is the only other candidate key (That is A + C B). A possible table could be Customer-Services (CustomerID, ServiceType, EmployeeID), assuming each employee provides only one service type, and each service type has several employees providing it.
R (A, B, C). In addition, A C and B C. A possible table would be ENROLLMENT(SID, CRN, Grade).
R (A, B, C, D) and A + B C, and C D. A possible table would be marriage registration table Marriage(H-SSN, W-SSN, recordedOnDate, recordedOnWeekDay).
R (A, B, C) and A B and A C. A PR (public relationships) firm’s VIP table VIP(VIP_ID, favorite_BooK_Authors, favorite_Sports)
An Example
R (A, B, C) and B C
A possible table for this would be Bad_Student (V#, LicensePlateCode, CarMaker). That is., in a student table, V# is the key. In addition, we store the student’s License Plate and the maker of his/her car with that License plate.
R is in 2NF because there is no partial dependency, but there is a transitive dependency between A and C. The splitting the relation results in R1(A, B) and R2(B, C).
What to turn in
Your TYPED answers, save in PDF, following the format in the given example, I prefer one page answers on this one.