Database Systems Department of Information Technology Database Systems

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 Poster. SQL 4. 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 Friday 9: 00 -10: 00 pm Tutorials Friday, 11: 00 -13: 00 B 0. 33 Lab Friday, 10: 00 -12: 00 am D 1. 01

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 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. n n n Readers buy books from you; Readers can order books from you; Readers can rent books from you. • Needs n n n 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: n n 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: 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 Approach File-oriented: n Data: represented in a convenient form. Database, BEA, 2000. 5, 12. 5 Jave, EFH, 2001. 2, 16. 5 ………… n n n 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, n n Expensive to develop/maintain the system Difficult in Manage Data. DB 1 DB 3 Program DB 2 DB 4

1. 4 Database Approach Database-oriented: n 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 n n 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. User 2 User 1 Database User 3 User 4

1. 5 What is a Database Relational DBMS - (RDBMS) n n 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: n n theoretical foundation – relational model. Logical data structure - Table. v a table has a name and is made up of named columns of data. Each row contains one value per column. Warehouse_No Location WH 1 Leeds WH 2 Bradford

1. 6 RDBMS Architecture Relational DBMS

1. 6 Advantage and Cost of a Database Approach ? ? ? Program ? !? ! Database

1. 6 Advantage and Cost of a Database Approach n Advantages: Database 1) without affecting the users. n Database may be tuned; n Database can be updated; 2) Data may be shared by many applications/users; 3) Greater security and integrity: n the data is collected together, n the data is managed by database administrator (DBA)

1. 6 Advantage and Cost of a Database Approach Database 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 n 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 n Before you go to Lab n n www. postgresql. org Before you come back for Tutorial n n Finish the exercise!! Any questions? ?