Computer Science CentreUniversity of Indonesia

In fo rm ationM anagem entR E S E A R C H G R O U P

Chapter 1

Database & Database Users

In fo rm ationM anagem entR E S E A R C H G R O U P

Applications of databases

• Banks• Hospital• Library• Supermarket• Magazine & newspaper

subscriptions

In fo rm ationM anagem entR E S E A R C H G R O U P

Extensions

• Multimedia databases• Geographic Information Systems• Data warehouse• On-line analytical processing

(OLAP)• Active & real-time databases

In fo rm ationM anagem entR E S E A R C H G R O U P

Definition

• Collection of related data which has meaning

• Examples: MS-Access, Oracle, Sybase, Informix, dBase, FoxPro

In fo rm ationM anagem entR E S E A R C H G R O U P

Properties

• Represents some aspect of the real world, called miniworld or Universe of Discourse

• Logically coherent collection of data with some inherent meaning

• Designed, built and populated for specific purpose

In fo rm ationM anagem entR E S E A R C H G R O U P

More example

• Small database: phonebook on your handphones!

• Large & complex database: tax office database

• Why is it much more complex?

In fo rm ationM anagem entR E S E A R C H G R O U P

DBMS

Database Management System is a collection of softwares that facilitates the process of – defining, – constructing and – manipulating

database for various applications

In fo rm ationM anagem entR E S E A R C H G R O U P

Database System Environment

In fo rm ationM anagem entR E S E A R C H G R O U P

‘University’ database example• Has 5 files (‘tables’):

– Student– Course– Section– Grade Report– Prerequisite

• See how do they relate to each other!• How do we define, construct &

manipulate?

In fo rm ationM anagem entR E S E A R C H G R O U P

In fo rm ationM anagem entR E S E A R C H G R O U P

Characteristic of Database Approach• Self describing nature• Insulation between program and

data• Support of multiple views of data• Sharing of data & multiuser

transaction processing

In fo rm ationM anagem entR E S E A R C H G R O U P

Self describing nature

• As oppose to unstructured data• Meta-data describes the structure

of the database• In traditional file processing, data

definition is part of the application program

In fo rm ationM anagem entR E S E A R C H G R O U P

Insulation between programs & data• Changes to the data structure does not

generally require changing the program• For example, adding a new field ‘Birthday’• The ‘data structure’ is not in the program• We call this program-data independence• DBMS provides conceptual representation• User or programmer does not need to know

how the DBMS store the data in the disk / file.

In fo rm ationM anagem entR E S E A R C H G R O U P

Multiple Views

In fo rm ationM anagem entR E S E A R C H G R O U P

Sharing & Multiuser

• DBMS provides concurrency control to ensure ‘correct’ behavior when multiple users update the same database

• Example: airline seat reservation• It is called On-Line Transaction

Processing (OLTP)

In fo rm ationM anagem entR E S E A R C H G R O U P

The Actors• Database administrator

– Authorizing access rights• Database designers

– Defines the structure of data to be stored• End users:

– Sophisticated non-programmer users– Naïve users

• Application programmers

In fo rm ationM anagem entR E S E A R C H G R O U P

Advantages of Using a DBMS• Controlling redundancy• Restricting unauthorized access• Provides persistent storage for data

structures• Permits inferencing• Multiple user interfaces• Represents complex relations amongst data• Enforcing integrity constraints• Provides backup & recovery

In fo rm ationM anagem entR E S E A R C H G R O U P

Implications of Database to Organizations• Could enforce standards• Reduce application development

time• Flexibility• Availability of up-to-date

information• Economies of scale