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 12); 2. Relational model and relational database management systems (weeks 2 -4); 3. Database languages and programming (4 -7) 4. (Relational) Database design (weeks 8 -
0. 3 Learning Strategy Lecture Tutorials 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 1. Lecturers: 2. 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) 2) 3) 4) 5) 6) To check the availability of a book; If this book is on order? How many book has a reader rent? If there is any book overdue? The charge to rent or buy a book ……
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: • Data: represented in a convenient Database, BEA, 2000. 5, 12. 5 form. 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 system Difficult in Manage Data. DB 1 DB 3 Program DB 2 DB 4 the
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) • 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. 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: 1) without affecting the users. n Database may be tuned; n Database can be updated; 2) Data may be shared applications/users; Database by 3) Greater security and integrity: n the data is collected together, n the data is managed by administrator (DBA) many database
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
- Slides: 27