OVERVIEW OF DATABASE MANAGEMENT SYSTEM

DATABASE APPROACH

      A database system is simply a computerized record - keeping system.The database can be regarded as a container for a collection of computerized data files.Uses of the database can perform

a variety of operations on such files - for example:

• Adding new,empty files to the database.
• Inserting data into from existing files.
• Retrieving data from existing files.
• Changing data in existing files.
• Deleting data from existing files.
• Removing existing files from the database.

COMPONENTS OF THE DATABASE ENVIRONMENT

    The nine major components of a Database Environment and their relationships are shown in the following figure:

REPOSITORY

   Centralized storehouse for all data definitions,data relationship,screen and report formats and other system components.A repository contains the important data for managing database and communication of other components of the entire system.

DBMS (DATABASE MANAGEMENT SYSTEM)

   It is a software used to define,create,maintain and provide controlled access to the database and also to the repository.

 DATABASE

   An organizational collection of logically related data,designed to meet the information needs of multiple users in organization.It is important to distinguish between the database and the repository.The repository contains definitions of data whereas the database contains actual data.

CASE TOOLS

   Computer Aided Software Engineering (CASE) tools used to design database and application programs.

APPLICATION PROGRAMS

   Computer programs that are used to create and maintain the database and provide information to users.

USER INTERFACE

   Languages,menus and other facilities by which users interact with various system components such as CASE tools,application programs,the DBMS,the repository and the database.

DATA ADMINISTRATORS

   Persons who are responsible for the overall information resources of an organization.Data administrators ( or Database Administrations (DBA)) uses CASE tools to improve the productivity of database design and planning.

SYSTEM DEVELOPERS

   Persons such as system analysts and programmers who design new application programs.System developers uses CASE tools for system requirement nalysis and program design.

END USERS

   Persons throughout the organization who add,delete and modify data in the database and who request to receive information from it.

All users interactions with the database must be routed only through the DBMS.