Department of Information Technology Database Systems Department of Information Technology

Database Systems – week 1 0. Introduction 1. Database Concepts

0.1 Aims or Objectives Fundamental of relational database; Understanding in relational data model; Knowledge and skills in the use of relational DBMS and PosterSQL Knowledge of database design.

0.2 What does it cover? Idea of database approaches (week 1-2); Relational model and relational database management systems (weeks 2-4); Database languages and programming (4-7) (Relational) Database design (weeks 8-10) Others: database administration, advanced databases etc. (weeks 11-12)

0.3 Learning Strategy Tutorials Lecture Lab

0.3 Learning Strategy Guided reading of the text book 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.

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 Lecturers: Teaching Assistants:

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 activities 1) 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 book 6) ……

1.1 What is a Database Books: Readers: Any More…….? Book_Title Authors Published date Price Relational Databases BEA 2000.5 12.35 Java EFH 2001.2 16.50   Readers: 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 Approach File-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 Approach Programs 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. DB1 Program DB2 DB3 DB4

1.4 Database Approach Database-oriented: Data: represented in table form. Book_Title Authors Published date Price Databases BEA 2000.5 12.35 Java EFH 2001.2 16.50   Database is central –designed and managed in its own right, by Database administrator (DBA). Programs are designed around the database.

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. User1 Database 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 Database Relational 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 Architecture Relational DBMS

1.6 Advantage and Cost of a Database Approach ????? ?!?! Database Program

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)

1.6 Advantage and Cost of a Database Approach 4) 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