DBMS - Introduction
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A Database is an organized collection of information.

A DBMS is a program that stores, retrieves, and modifies data in the database on request.

There are four main types of databases : hierarchical, network, relational, object relational. (Oracle 7 is a relational dbms and oracle 8 is an object relational dbms)

 

Component of the relational model ;

• Collection of objects or relations (tables) that store the data
• A set of operators that can act on the relations to produce other relations
• Data integrity for accuracy and consistency

 

A relational database uses relations or two dimensinal tables to store information.

Eg. To store information about all the employees in your company, you create several tables to store different pieces of information about your employees, such as an employee table, a department table, and salary table.

 

Object Relational DBMS :

1. User-defined data types and objects
2. Fully compatible with relational database
3. Support of multimedia and large objects

High-quality database server features