ORACLE INTRODUCTIN

ORACLE INTRODUCTION

Before database was invented, File system is used to store data in computers. Because of the disadvantages like data redundancy, atomicity, consistency and security in file system, Database Management System (DBMS) was introduced. Collection of related data is called as Database. Collection of inter-related data and a set of programs to access those data is called as Database Management Sysytem (DBMS). Oracle is a Database Management System Software.

After DBMS came in to practice, several models are proposed in DBMS with different types of storage methods for the data within the database. Among them Relational Database Model is the widely used data model. Relational Database model was proposed by E.F.Codd. In Relational Database Model, Data is stored in the form of relations or tables. A table is comprised of rows and columns. A row is also called as a Tuple and a column is called as an Attribute. Relational Database Model was developed based on the concepts of Relational Algebra and Relational Calculus.

Another development in DBMS is introducing Object Oriented Programming (OOP) concepts in DBMS. By this concept, new database models called Object Oriented Database Models were introduced. A new model called Object Relational Database Model was developed by incorporating OOPS concepts in relational database model.

Upto Version 7.3, Oracle is Relational Database Management System Software. But from version 8.0 onwards, Oracle is Object Relational Database Management System Software (ORDBMS). After version 8.0, Oracle version 8i was released. In this version, Oracle has provided the features by using which we can interact with the Internet. After Version 8i, another version 9i was released. Most of the new features in 9i are towards the Architecture and DBA related and some new features are added towards application development side.

Oracle Provides several tools to access the database. Among them the tools that are covered in this book are SQL, PL/SQL, FORMS and REPORTS. Forms and Reports are combinedly called as Developer/2000 or simply D2k. New version of D2k is 6i and is released along with database release 8i.