Ch6. Introduction to Database

What is a Database?

• Database is a collection of related information.

• It is organized so that it can easily be accessed, managed, and updated.

In the past…Information storage & retrieval

Index card in a library

In the past…Information storage & retrieval

Customer information on index cards

Present..Use of database will…

Reduced data entry, storage, and retrieval costs.

Present..Use of database will…

Multi users access database at the same time.

Present..Use of database will…

Data Security is improved. Login is needed &

different users have different access right to database.

Examples of database system

Personal phone book

Examples of database system

Employee records of a company

Examples of database system

Stock control of a supermarket

Examples of database system

Student records of a school

Hierarchy of data organization

Database Management System

Ensure Data Integrity

• Continues to be accessible. • Consistently organized.

Ensure Data Security

• Make sure only those with right can access the data.

• i.e. Username and password is needed to access the data. (Microsoft Access don’t have this function)