Database Management Systems (dbms)

Solution - A company Database Detailed Conceptual Design

• Step One
• Identify entity types, attribute on each entity.
• Department

DEPARTMENT
Number
Location
Name
Note : Name or number can be the key

Step One - Identify entity types & attribute

• Project

Project
Number
Location
Name
Name
surname
FN
Employee
Address
i.d#
Salary
Sex
Dob
Number
street
city
3. Employee

Step One - Identify entity types & attribute..

• Dependent

Dependent
Name
Dob
Sex

Step Two - Identify relationship types

• “A particular employee who manages the department”
• Assumptions:
• An employee can manage one department.

A department is manage by only one employee.

• A department must have a manager at all times. (Total)

Employee
Department
Manages
1
1
1:1

Step Two - Identify relationship types..

• “A department controls a number of projects.”

Assumptions:

• A project is controlled by one department.

A department controls number of projects.

• A project must be controlled by a department. (Total)

Department
Projects
Controls
1
M
1:M

Step Two - Identify relationship types..

• “An employee is assigned to one department but many worked on several project.”
• Assumptions:
• A department has many employee.
• An employee must belong to a department and department must have employees. (Total)
• A project may have employees
• An employee can work on a project and a project