Database Systems

Department of Information Technology

Database Systems – week 1

0. Introduction

1. Database Concepts

0.1 Aims or Objectives

1. Fundamental of relational database;2. Understanding in relational data

model;3. Knowledge and skills in the use of

relational DBMS and PosterSQL4. Knowledge of database design.

0.2 What does it cover?1. Idea of database approaches (week 1-2);2. Relational model and relational database

management systems (weeks 2-4);3. Database languages and programming (4-7)4. (Relational) Database design (weeks 8-10)5. Others: database administration, advanced databases etc. (weeks 11-12)

0.3 Learning Strategy

Lecture Tutorials Lab

Friday 9:00-10:00pm

Friday, 11:00-13:00B0.33

Friday, 10:00-12:00amD1.01

0.3 Learning Strategy

A) T. M. Connolly, C. E. Begg, Database Systems: A Practical Approach to Design, Implementation, and Management (Fourth Edition), Addison-Wesley, 2004.ISBN: 0-321-21025-5, URL: http://www.booksites.net/connolly

B) Eaglestone.BM, Relational Databases, Stanley Thornes,1991.

Guided reading of the text book

0.4 Learning Assessment

A) Course work (20%)• SQL Lab Test (10%): Week 10.

• Database Design (10%): Week 10.

B) Exam (80%): Jan 2007.

0.5 Teaching Team

1. Lecturers: • Yonghong Peng • Geyong Min

2. Teaching Assistants:• Ph.D. Students.

0.6 Schedule and Resources

http://www.comp.brad.ac.uk/intranet/modules/DS/

Or from the link shown in the BB.

1.1 What is a Database System?Scenario: You are a book shop owner.

Readers buy books from you; Readers can order books from you; Readers can rent books from you.

• Needs if a book (how many copies) is available? Which book has this reader rented? If it is overdue? Which book has this reader ordered? When will a ordered book become available?

1.1 What is a Database System?

1. What Information do you need to for managing your book shop?

2. What management activities are involved?

3. How to design a computer system to help the staff to manage all the activities?

1.1 What is a Database System?

1. Information needed: Books (authors, title, price); Readers (name, address, telephone, ordered book, books rent) Books in shop; Books on order;

1.1 What is a Database System?

2. Management activities1) To check the availability of a book;2) If this book is on order?3) How many book has a reader rent?4) If there is any book overdue?5) The charge to rent or buy a book6) ……

1.1 What is a Database

Books:

Readers:

Book_Title Authors Published date Price

Relational Databases BEA 2000.5 12.35

Java EFH 2001.2 16.50

       

Name Address Telephone

Eric Leeds 0113-

Peter Bradford 01274-

       

Any More…….?

1.2 How to implement the Database Management

Interaction between Data and Programs

Data Program User

1.3 Conventional ApproachFile-oriented:

Data: represented in a convenient form. Database, BEA, 2000.5, 12.5

Jave, EFH, 2001.2, 16.5…………

Need to design the data files for a specific activity;

Database does not exist as a single structure,

Database is distributed across a number of files.

1.3 Conventional ApproachPrograms are central, need to know:

• how the files are organized?• how records may be accessed, and the meaning of

data?As a result, Expensive to develop/maintain the system Difficult in Manage Data.

DB1Program

DB2

DB3 DB4

1.4 Database ApproachDatabase-oriented: Data: represented in table form.

Database is central –designed and managed in its own right, by Database administrator (DBA).

• Programs are designed around the database.

Book_Title Authors Published date Price

Databases BEA 2000.5 12.35

Java EFH 2001.2 16.50       

1.5 What is a Database Database management system (DBMS):

a type of computer program, which is used to manage data stored on a computer;

DBMS aims to enable other programs and users to make use of that data.

User1Database

User2

User3 User4

1.5 What is a Database

Relational DBMS - (RDBMS) one of the wide used and the easies to

operate database systems. Relational data model – the basis of

RDBMS.

1.5 What is a DatabaseRelational DBMS - RDBMS:

theoretical foundation – relational model.

Logical data structure - Table. a table has a name and is made up of named

columns of data. Each row contains one value per column.

Warehouse_No Location

WH1 Leeds

WH2 Bradford

1.6 RDBMS ArchitectureRelational DBMS

External Model A External Model n

Program 1 Program 2 Program n

Logical Model

Internal Model

Device ModelHardware Level

Physical Level

Global Level

DBMS

Datadictionary

Database

1.6 Advantage and Cost of a Database Approach

Program

????? ?!?!

Database

1.6 Advantage and Cost of a Database Approach Advantages:

1) without affecting the users. Database may be tuned; Database can be updated;

2) Data may be shared by many applications/users;3) Greater security and integrity:

the data is collected together, the data is managed by database administrator (DBA)

Database

1.6 Advantage and Cost of a Database Approach4) Greater productivity - easier and faster to create applications programs - NO need to include details of how the data are

physically stored; - NOT necessary to change applications programs

when the database is changed; - NO need to be re-store the data for new

applications.

1.6 Advantage and Cost of a Database Approach Costs:

1) requires more hardware resources - a minimum requirement in order to run the DBMS.2) additional software is required to support the database approach - need extend programming languages.3) Cost of employing DBA team.

1.7 Your Homework Before you go to Lab

www.postgresql.org

Before you come back for Tutorial

Finish the exercise!! Any questions??