August 1999
DB212 : DATABASE MANAGEMENT SYSTEMS

QUESTION 3

Total Marks: 20 Marks

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SUGGESTED SOLUTIONS
Solutions and allocated marks are indicated in green.
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(a) What is the Relational Database Model? Briefly explain the different components of the model. [7]
The Relational Database Model is a model that represents data in the form of tables of relations.

The components of the Relational Database Model are:

  • Data structure : Data are organized in the form of tables or relations
  • Data Manipulation : Powerful operations such as SQL languages or Query-By-Example, are used to manipulate data stored in the database
  • Data integrity : Business rules are specified to maintain the integrity of data when they are manipulated

 
(b) The figure below shows a grade report that is produced at the end of each semester for students at a college. Prepare an Entity Relationship Diagram for the Grade Report. You may assume that each course is taught by just one instructor.

 

King Arthur's College
Grade Report
Spring Semester 1997
Name : John Smith
Campus address : 25 Lancelot Crescent		 Student Id: 961005123
Major: Computing
Course Id Title Instructor Instructor Location Grade
IS 350

BN 670

 DB Management

Systems Design

 Wood

Clarence

 C100

A102

 A

B

 

 [9]

pic4.gif (17370 bytes)

 
(c) Derive the corresponding relations for the Entity Relationship Diagram you have given in part (b). [4]
Student(Student ID, Student Name, Campus Address, Major)

Course (Course ID, Title, Student ID, Instructor Name)

Instructor (Instructor Name, Instructor Location)

Enrolment (Student ID, Course ID, Semester Grade, Grade Received)