BSc (Hons) Web Technologies, BSc (Hons) Business Information System. Examinations for / Semester 2. Resit Examinations for BIS/15B/FT

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1 BSc (Hons) Web Technologies, BSc (Hons) Business Information System Cohorts: BWT/16B/FT & BIS/16B/FT Examinations for / Semester 2 Resit Examinations for BIS/15B/FT MODULE: DATABASE MANAGEMENT SYSTEM MODULE CODE: DBT1101 Duration: 2 Hours 30 Minutes Instructions to Candidates: 1. Attempt ANY FOUR questions. 2. Questions may be answered in any order but your answers must show the question number clearly. 3. Always start a new question on a fresh page. 4. Total marks 100. DO NOT TURN PAGE OVER UNTIL INSTRUCTED Page 1 of 7

2 QUESTION 1 [25 Marks] (a) Explain the difference between Logical and physical data Independence? (b) Define the following terms: (i) An Entity (ii) An Attribute (iii) A Relationship (c) Explain the different types of attributes that occur in an ER diagram model and show how each attribute will be represented in the ER Model with an appropriate example for each. [4 x 3 marks] (d) A Null can represent one of the following: An unknown attribute value. A known, but missing, attribute value. A not applicable condition. Provide an example of each one of the above condition. Page 2 of 7

3 QUESTION 2 [25 Marks] (a) Describe the types of anomalies that may occur on a table that has redundant data. Support your answer with an appropriate example of each using the table given below. (b) Referring to the table structure shown below: (i) Identify all the dependencies between data items (including all partial and transitive dependencies) and Identify the Primary Key of this table. [6 marks] (ii) Normalize the table to 3NF showing all the intermediate steps (i.e., 1NF, 2NF and 3NF) using the bracketing notation. Where: C_Lname means Client Last Name C_Fname means Client First Name C_Mobile means Mobile no. of Client Rent_Start means Start date of Rental Rent_End means End date of Rental P_No means Property Number O_No means Owner Number O_Lname means Owner Last name [12 marks] Table Showing details of Property Rental Client_No C_LName C_FName C_Mobile Rent_Start Rent_End P_No P_Address Rent_Price _Per_Day O_No O_Lname O_Fname 8 Lawrence Street, CL100 Abraham John Jan Jan-17 PT5 Pereybere Rs3,000 CO40 Murphy Mina CL100 Abraham John Dec Dec-16 PT25 12 Alvin Drive, Tamarin Rs5,000 CO90 Jugnath Ravin CL170 Wayne Rooney Dec-16 3-Jan-17 PT25 12 Alvin Drive, Tamarin Rs5,000 CO90 Jugnath Ravin CL170 Wayne Rooney Jan Mar-17 PT Azuri Drive, Azuri, Roches Noires Rs12,500 CO90 Jugnath Ravin CL100 Abraham John Dec Dec-16 PT Azuri Drive, Azuri, Roches Noires Rs12,500 CO90 Jugnath Ravin (c) Draw an ERD from the tables obtained through the Normalization Process above. Page 3 of 7

4 QUESTION 3 [25 Marks] (a) Use the following business rules to produce the Logical Data Model for the system. A department employs many employees, but each employee is employed by one department. Some employees, known as "rovers," are not assigned to any department. The identifier for employee is employee_id and other attributes include E_LastName, E_FirstName, DOB, Address, Hired_Date. The identifier for department is department_id and other attributes include department_name and location. A division operates many departments, but each department is operated by one division. The identifier for division is division_id and other attribute include division_name An employee may be assigned to many projects and a project may have many employees assigned to it. A project must have at least one employee assigned to it. The company also wants to keep record of the number of hours each employee spends on a project. The identifier for project is project_id and other attributes include project_name and project_budjet. One of the employees manages each department. One of the employees runs each division. [12 marks] (b) Map the ERD produced into its equivalent Relational Schema(Physical Model) [13 marks] Page 4 of 7

5 QUESTION 4 [25 Marks] This question refers to the database Schema given in Appendix I. (a) Express the following queries using SQL (i) Write the SQL code that will create the LOCATION table as given in the appendix. Your answer should not contain the Primary Key Constraint. (ii) After creating the Location table, write SQL code to make the LOC_ID the Primary Key of the Location table. (b) Write the SQL code that will create the STUDENT table as given in the appendix. Your answer should include the Primary Key and Foreign Key constraints. (c) Assuming that all the tables have been created as given in the relational schema in the Appendix, write SQL code to make the following changes in the structure of the tables. (i) Create a constraint in the STUDENT table for the S_CLASS column, so that it will only accept the following values: FR, JR, SR AND SO (ii) Create a constraint for the F_PIN in FACULTY table, so that no two person will have the same PIN number. (d) Write SQL code to insert the first row in the Location table. (e) Write SQL code which will modify the student class value of the student Amanda Mobley to SR. (f) (g) (h) (i) Retrieve the S_CLASS field values for all rows in the Student table and suppress duplicate output. Sort the result in alphabetical order. Retrieve the S_FIRST, S_LAST, and S_MI field values for every student who does not have a value for S_MI. Retrieve the S_FIRST, S_LAST, and S_DOB field values for all students whose S_CLASS value is either JR or SR. Retrieve the S_FIRST, S_LAST and S_DOB field values for all students who were born during Page 5 of 7

6 QUESTION 5 [25 Marks] This Question is based on the data shown in Appendix. (a) Draw an Entity-Relationship model for the relational schema given in the Appendix. Show all the entities, relationships, relationship names, and attributes and also underline the primary key for each entity. (b) Explain the following statements in relational algebra, and give the expected values of the table RESULT when using the initial values of the STUDENT, FACULTY and LOCATION tables provided in the appendix. (c) (i) RESTRICT LOCATION WHERE BLDG_CODE = BUS GIVING T1 JOIN T1 AND FACULTY OVER LOC_ID GIVING T2 JOIN T2 AND STUDENT OVER F_ID GIVING T3 PROJECT T3 OVER S_LAST, S_FIRST, F_LAST, F_FIRST, BLDG_CODE, ROOM GIVING RESULT [5 marks] (i) PROJECT FACULTY OVER F_ID GIVING T1 PROJECT STUDENT OVER F_ID GIVING T2 T1 MINUS T2 GIVING T3 JOIN T3 AND FACULTY OVER F_ID GIVING T4 PROJECT T4 OVER F_FIRST, F_LAST GIVING RESULT Express the following queries firstly using Relational Algebra and then secondly using SQL. (i) Get the last name of student who is counselled by the faculty named Kim Cox. [3 + 3 marks] (ii) Get the last name of faculty whose offices is found in the library (i.e.,bldg_code = LIB). [3 + 3 marks] Page 6 of 7

7 APPENDIX The following relational database shows part of the record of students, location and faculty member for a University. Select * from faculty; Select * from location; Describe Student; Select * from Student; ***END OF PAPER*** Page 7 of 7