Quiz 2
1. Instruction:
 Use the following set of business rules to draw an ERD.
 Eliminate all M:N relationships.
 Make sure to write in all appropriate cardinalities and connectivity.
 Explain all your decisions to include optional relationships.
The business rules:
a. A department employs many employees, but each employee is employed by one
department.
b. Some employees, known as "rovers," are not assigned to any department.
c. A division operates many departments, but each department is operated by one division.
d. An employee may be assigned to many projects, and a project may have many
employees assigned to it.
e. A project must have at least one employee assigned to it and Employee maybe not
assigned to many project.
f. One of the employees manages each department, and each department is managed by
one employee.
g. One of the employees runs one division, and each division is run by one employee.
(10 marks)
Answer:
1
employ
m
1
manage
1
Department
Employee
M
1
Operates
1
Division
m
runs
assign
1
m
Project
2. Explain the phases in Database Life Cycle (DBLC).
(10 marks)
Answer:
3. a) Differentiate Distributed Database Management System with centralize Database Management
System.
Answer:
•
Distributed database management system (DDBMS)
–
•
Governs storage and processing of logically related data over interconnected computer
systems in which both data and processing functions are distributed among several sites
Centralized database required that corporate data be stored in a single central site
b) Draw a diagram to show Distributed Database Management System.
Answer:
c) Draw a diagram to show centralize Database Management System.
Answer:
4. Briefly explain the following issues on database security:
a) Theft and fraud
b) Loss of confidentiality (secrecy)
c) Loss of privacy
d) Loss of integrity
e) Loss of availability