Part 4. (12 marks) Given a database consisting of one first normal form relation
ID: 3702660 • Letter: P
Question
Part 4. (12 marks) Given a database consisting of one first normal form relation SECOND with attributes A, B, C, D, E, and the functional and multi-valued dependencies as well as the functional and the multi-valued dependency diagram as follows SECOND Functional Dependencies {AB-»C, C B Multivalued Dependencies {C->D, C--» E) Dependency Diagram 1. What is the key for SECOND? (2 marks) 2. What is the highest normal form this relation is in? (2 marks) 3. Normalize the relation into BCNF by giving its relation names, their attributes with primary keys underscored and foreign keys pointing to the corresponding attributes properly and its dependency diagrams as showing above (4 marks) Normalize the result in the third question into the fourth normal form by giving its relation names, their attributes with primary keys underscored and foreign keys pointing to the corresponding attributes properly and its dependency diagrams as showing above (4 marks) 4.Explanation / Answer
Answer 1: AB is the key as it can derive A,B and C. D & E are from C(through multivalued dependency).
Answer 2: Third Normal Form.
Answer 3: To convert into BCNF, decompose the table into R1(ABC) , R2(BCDE), where AB is the primary key in R1 and C is the foreign key of R1 referring to the primary key C of R2.
Answer 4: To convert into 4NF, the given relation should be decomposed into R1(ABC) , R2(CD) and R3(CE) , where AB is the primary key, C is the foreign key pointing to primary key C of R2 and R3.