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??
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