Module 1: Database System

Overview Introduction Traditional File Based System Database Approach Roles in Database Environment The History of Database System Advantages and Disadvantages of Database Systems

Introduction Database is now such an integral part of our day to day life. We can consider a Database to be collection of related data . DBMS to be a software that manages and controls access to the database

Traditional File Based System A Collection of application programs that perform services for the end users such as the production of reports. Each file define and manages its own data Data Entry And Reports File handling Routine Sale File File Definition Sale Computer Data Entry And Reports File handling Routine File Definition Contract Computer Contract File

Limitations of the File-Base Approach Separation and isolation of data Duplication of data Data dependence Incompatibility of data Fixed queries

Database Approach A shared collection of logically related data (and a description of this data), design to meet the information needs an organization DBMS A software system that enables users to define, create and maintain database and which provides controlled access to this database. DDL DML DCL

Components of DBMS Environment Hardware Software Data Procedures People Data Hardware Software Procedures People Bridge Machine Human

Roles in Database Environment Data and Database Administrator Data Administrator (DA) Planning Database Administrator (DBA) Physical Database Designer Application programmers End User Native User Sophisticated User

The History of Database System 1960s Apollo moon-landing project need a database North American Aviation(Now Rockwell International) develop a software GUAM(Generalized Update Access Method) based on smaller components come together as a part of large component. This structure also known as hieratical structure. Mid 1960s IBM joined NAA to develop GUAM now known as IMS (Information management system) Mid 1960s another significant development IDS (Integrated Data Store) from General Electric.

The History of Database System 1967 US govt. assigned a task to Database Task Group (DBTG) to define standard. DBTG released a first report which identified three components in 1969. Network Schema---Database definition seen by the DBA (DDL) Subschema---seen by user and application program (DDL) Data Management language—data characteristics (DML)

The History of Database System This report was not formally adopted by ANSI(American National Standards Institute) 1970, E.F Codd of IBM produce a concept of relation data model It has two major development SQL (Structure Query Language) RDBMS in 1980s DB2 and SQL/DS from IBM and Oracle from Oracle Corporation. (First Generation) Second Generation (RDBMS) Paradox and dBase IV from Borland, Access from Microsoft, FoxPro and R:base from Microrim. Third Generation Object Oriented Data Model (OODM) Extended Relation Data Model (ERDM)

Advantages and Disadvantages of Database Systems Control of data redundancy Data consistency More information from the same amount of data Sharing of data Improved data integrity Improved security Enforcement of standards Economy of scale

Advantages and Disadvantages of Database Systems Balanced conflating requirements Improved data accessibility and responsiveness Increased productivity Improved maintenance through data independence Increased concurrency Improved backup and recovery services

Advantages and Disadvantages of Database Systems Complexity Size Cost of DBMS Additional Hardware cost Cost of Conversion Performance High impact of failure