•Data are symbols which represent, describe, or record facts

•Data are collection of facts related to events, objects etc

•Data are in unorganized form but can be organized into useful information

•Traditionally, data were stored in files containing papers or other materials and this system is still in quite prevalent , updated and retrieved manually whenever needed.

•This manual system has lot of problem sin retrieval

•These problems have been reduced after the use of computers for data management

•In order to overcome the problems of traditional file management , a new system was evolved , known as database management systems

Traditional file management

• Also known as traditional data management or traditional file processing

• It involves storing data into files which can be accessed , manipulated, updated and worked

• A file contains records of the same type , a record or other collection of information stored on a disk and identified as a unit by a unique name

• A record in the file describes entity (sales order is an entity in a sales file which maintains information about an organization’s sales order)

• an entity may have different characteristics known as attributes(a sales order may have an order no, order date, order amount, item number, and item quantity)

• Every record in a file should contain at least one field that uniquely identifies that record so that record can be retrieved , updated or stored.(key field)

• Depending on the storage and access methods ,files can be classified as:

1. Sequential Access File

2. Indexed sequential access File

3. Direct Access File

PROBLEMS IN TRADITIONAL FILE MANAGEMENT

1. DATA REDUNDANCY

2. PROGRAM-DATA DEPENDENCE

3. LACK OF FLEXIBILITY

4. ATOMICITY PROBLEM

5. LACK OF SECURITY

6. LACK OF DATA SHARING

DATABASE MANAGEMENT SYSTEM

• A database management system consists of a collection of interrelated data and programs to access those data

• A database management is simply the software that permits an organization to centralize data, manage them efficiently, and provides access to stored data by application programs.

CHARACTERISTICS

• DBMS has the capacity to store large amount of data necessary for user’s needs, They are stored on direct accessible devices

• It has the capacity to interrogating the data files ,retrieving and modifying data and recording the changes

• The data are combined to form operational units to minimize the duplication of data and increase access to all data in the database

• The control in the system limits access to the database and builds the confidentiality of data in the database

• The advancement in the database enables to add more data and program to the system

Objectives of DBMS

• Complexity of than organization’s IS is reduced through centralization of the data management

• Data redundancy and inconsistency are reduced and data security is increased by eliminating all isolated files in which the same data elements are repeated. With the result, data management cost is reduced significantly.

• Program data dependence is reduced by providing central control of data creation and definition

• Flexibility in IS is greatly increased by permitting queries of laarge pool of information.

• Data, once stored are accessed by multi-user.

COMPONENTS OF DBMS

1. DATABASE ADMINISTRATOR

• Schema definition• Storage structure and access method definition• Schema and physical-organization modification• Authorization of data access• Integrity –constraint specification

2. DATABASE USERS

• Application programmers• Specialized users• Naïve users• End users

3. DATABASE SOFTWARE

– Data definition language

– Data manipulation language

– Query language

– Report generator

4. DATABASE