Dr. R.A.N.M ARTS AND SCIENCE COLLEGE�Affiliated to Bharathiar University , �Accredited with “ B+” NAAC
Mrs. D.MAGESWARI M.Com(CA)., M.Phil B.Ed., MBA.,
Assistant Professor,
Department of Commerce (CA)
Course Name : Database Management System
Welcome You All
Data base system
Database system is nothing more than a computer-based record keeping system (i.e.) a system whose overall purpose is to record and maintain information. The information concerned can be anything that is deemed to be of significance to the organization or the system which may serve the organization in decision-making processes involved in the management of that organization.
Data
The data stored in the system is partitioned into one or more databases. A database is a repository for stored data, it is of both integrated and shared.
Integrated:
By integrated we mean that the database can be thought of as a unification of several distinct files, with the redundancy among those files eliminated.
Example: Combination of EMPLOYEE and ENROLLMENT data files.
Hardware
The hardware consists of the secondary storage device disks, drums,etc… on which the database resides together with the associated devices, control units, channels and so forth.
Software
Between the physical database and the users of the system is a layer of software usually called the DBMS .All requests from users for access to the database are handled by the DBMS .One general function provided by the DBMS is thus the shielding of the database users from hardware level. The DBMS provides a view of the database that is elevated somewhat above the hardware level and supports user operation that are expressed in terms of that higher-level view.
Users
There are three broad categories of database users, they are
*application programmers
*end-users
*DBA
Application programmer is responsible for writing application programs that use the database. These application programs operate on the data in all the usual ways that is in retrieving information, creating new information, deleting or changing existing information.
2.End-users
End-users access the database from a terminal. An end-user may employ a query language provided as an integral part of the system or may invoke a user-written application program that accepts commands from the terminal and in turn issues requests to the DBMS on the end-user’s behalf.
3.Database Administrator
DBMS have central control of both the data and to the programs that access those data. The person who has such control over the system is called DBA. The main functions of DBA
A database is a collection of stored operational data used by the application systems of some particular enterprise. Where enterprise is a conventional generic term for any reasonably self-contained commercial, scientific, technical or other organization.
Examples.
Manufacturing company, Bank, Hospital, University, Government department etc. The enterprise should maintain a lot of data about its operation. The “operational data” for the enterprises quoted above are,
Product data, account data, patient data, student data, planning data.
Thankyou