MSIS 635 DATABASE MANAGEMNT Database Systems Thomas Connolly and Carolyn Begg Third Edition – 2002 – ©Addison Wesley

PART I – BACKGROUND Chapter 1- Introduction to Database Chapter 2 – Database Environment

Introduction – Some Database Applications Purchases from Supermarket Purchases using Credit Card Booking a holiday at the travel agents Using the local library Taking out Insurance Using the Internet Studying at the University

Introduction - Traditional File Based Systems A collection of application programs that perform services for the end-users such as the production of reports. Each program uses and manages its own data Limitations of file-based approach Separation and isolation of data Duplication of data Data dependence Incompatible file formats Fixed Queries, proliferation of application programs

1.3 Database Approach Database – A shared collection of logically related data, and a description of the data, designed to meet the information needs of an organization. Centralized? (Vijay) – pp.15 Database Management System (DBMS) – A software system that enables users to define, create, maintain and control access to the database. Views

Components of the DBMS Hardware Software Data Procedures Log on Use a DBMS facility for application programs Start and stop the DBMS etc…

Roles in the Database Environment Data and Database Administrators Database Designers Application Developers Users

Advantages of DBMSs Control of data redundancy Data Consistency More Information from the same data Sharing of data Improved data Integrity Improved Security Enforcement of Standards

Advantages of DBMSs Contd Economy of Scale Balance of Conflicting Requirements Increased Productivity Improved Maintenance through data independence Improved Concurrency Improved backup and Recovery of data

Disadvantages of DBMSs Complexity Size Cost of DBMS Cost of Conversion Performance Higher Impact of failure